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# Yarr Buster a software anti-piracy protection technique

## Recommended Posts

Octarinne    123
Hello,

I've been working on a protection technique that I think has never been tried. I protects a program by encoding the serial protection in the source and generating a unique .exe for every user. Each serial can only be used with the corresponding .exe. If you want to see some source and know more about this technique, please visit the Yarr Buster site here:

http://software.collectionsbp.com/YarrBuster/

and let me know what you think here!

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Sounds cool, but what's to prevent a hacker from just copying the program, with the same serial key? Couldn't he just distribute his key with his version of the program?
Even if a developer makes the serial key "call home" to verify it's not been used before, the hacker could merely disable the call home part, and the whole thing falls apart. (Security is only as strong as the weakest link - break the weakest part and everything else doesn't matter)

Quote:
 7 - Unprotect code that should be fast by loading the original project and copying the old code over the protected code that should not be protected.

What if the project is thousands of files, and hundreds of thousands of lines of code? You'd have to copy and paste plenty of the original code, manually.
Wouldn't a better idea be to use source comments, and do something like this:
..code I don't want protected (due to speed issues or whatever).//<YarrBuster>..code that Yarr buster can mess with.//</YarrBuster>..code I don't want encrypted.

[Edited by - Servant of the Lord on October 10, 2010 4:47:04 PM]

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Octarinne    123
Quote:
 Original post by Servant of the LordSounds cool, but what's to prevent a hacker from just copying the program, with the same serial key? Couldn't he just distribute his key with his version of the program?

You're right. He could. You could always link the serial to the hard disk of the user but I personally don't like this since I like to be able to install software after a long time on a new system. The technique I am proposing is not 100% efficient but it's the most effective technique I could come up with that isn't penalizing to a legitimate user.

Quote:
 Even if a developer makes the serial key "call home" to verify it's not been used before, the hacker could merely disable the call home part, and the whole thing falls apart. (Security is only as strong as the weakest link - break the weakest part and everything else doesn't matter)

The call home thing is for program that require an on-line connection to use like on-line games for example. My technique would ensure that only legitimate users could connect. Still, without my technique if the server checks for a correct serial it should avoid piracy as far as I know.

Quote:
 Wouldn't a better idea be to use source comments, and do something like this:..code I don't want protected (due to speed issues or whatever).//..code that Yarr buster can mess with.//..code I don't want encrypted.

Yes it would, excellent idea. The source I have provided is only a prototype to demonstrate how the protection works, there's room for improvements. Thanks for your comments and suggestion!


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# make quote'' output as “quote„

I have a document in which everything is quoted in the form:

quote''

How do I make them appear in the output document as

“quote„

thanks

• You can't: \csquotes has its own commands and doesn't act on explicit quotes. – egreg Oct 10 '13 at 15:46
• @Geremia -- If no one comes up with a better solution, you may try \def\lq{\raisebox{-6pt}{''}} and then use an editor to replace all right '' with \lq. Not fully automatic yet, this may point a direction to a solution. – Jesse Oct 11 '13 at 7:45
• @Jesse If you do something like that, you can drop some crazy \raisebox and use \textquotedblbase. Or skip \lq entirely and use csquotes package. – yo' Mar 17 '14 at 10:42
• Since you have some responses below that seem to answer your question, please consider marking one of them as ‘Accepted’ by clicking on the tickmark below their vote count (see How do you accept an answer?). This shows which answer helped you most, and it assigns reputation points to the author of the answer (and to you!). It's part of this site's idea to identify good questions and answers through upvotes and acceptance of answers. – user36296 Oct 24 '16 at 19:06

Here's something that works for me. It is based on making the right single quote an active character in TeX. I must admit I have no confidence that this doesn't break something else, especially in the light of the negative comment by @egreg to the original question.

Let's start with an example that contains a number of quotations. The first line shows how we would like double quotes to appear.

\documentclass[12pt]{article}
\usepackage[T1]{fontenc}

\begin{document}
This is the \textquotedblleft{}quote\quotedblbase{} that I'd want.

Let's play with some double quotes'' and
some more double quotes''            and yet some more''
and then with some single quotes' and
some more single quotes'          and yet some more'
and see what happens.
\end{document}

Now, by adding the following lines to the preamble:

\makeatletter
\catcode'=\active
\def'{\futurelet\@rqpeek\@rqhack}
\def\@rqhack{\ifx\@rqpeek'\expandafter\dbl@rq\else\rq\fi}
\def\dbl@rq'{\quotedblbase}
\makeatother

you can get what you want.

EDIT: After egreg's comment about this tweak breaking math that contains primes, like $f'(x)$, I'm providing a fix and concluding with a brief explanation and a disclaimer.

\documentclass[12pt]{article}
\usepackage[T1]{fontenc}

\makeatletter
\catcode\'=\active
\def'{\ifmmode\expandafter\active@math@prime\else\expandafter\@rqtext\fi}
\def\@rqtext{\futurelet\@rqpeek\@rqhack}
\def\@rqhack{\ifx\@rqpeek'\expandafter\dbl@rq\else\rq\fi}
\def\dbl@rq'{\quotedblbase}
\def\pr@m@s{%
\ifx'\@let@token
\expandafter\pr@@@s
\else
\ifx^\@let@token
\expandafter\expandafter\expandafter\pr@@@t
\else
\egroup
\fi
\fi}
\makeatother

\begin{document}
This is the \textquotedblleft{}quote\quotedblbase{} that I'd want.

Let's play with some double quotes'' and
some more double quotes''            and yet some more''
and then with some single quotes' and
some more single quotes'          and yet some more'
and see what happens.

Let's see some math too:
if $f(x) = x^2$ then $f'(x) = 2x$ and
$$f''(x) = 2$$

And some more single' and double'' quotes.
\end{document}

The fix comes in two parts. First the active quote has to check whether it's found in math mode or text mode. Second, the internal macro \pr@m@s (handling successive primes in math mode) has to be repeated here (verbatim from latex.ltx) because it checks whether the next character is ' and now it has to check for an active '.

Disclaimer: Making the single right quote an active character is expected to break everything that already treats it as an active character. Examples that cross my mind are: the babel package (some languages with accents), various math packages like euler, various verbatim-text packages like the alltt. But there are also packages, like xspace which (temporarily) set the \catcode of \' to 13. I've tested euler, alltt and xspace and they seem to work fine with this. All this said, you have been warned. If a package breaks with this, I don't expect the fix to be obvious...

• Of course this breaks math $f'(x)$, which is one of the drawbacks. – egreg Oct 12 '13 at 0:13
• @egreg: If that's the only problem, I guess it can be fixed by making '` non-active when in math mode. – nickie Oct 12 '13 at 0:17
• @egreg: math was easy, I'm updating the answer. I'll explain what else is expected to break and I'll stop here. – nickie Oct 12 '13 at 1:33

format: plain


text:
# Length of Wire

Algebra

### Length of Wire

A cubical piece of iron 3 inches on a side is formed into a wire 1/32 in. in diameter. Determine wire length.

Pi = 3.1416

Volume of cube = 27 cu. in.

Wire is a cylinder- pi * r^2 * height (or length).

3.1416 * 0.015625 * 0.0156125 * l = 27. Volume of iron = volume of wire.

0.00765765490875l = 27

0.00765765490875l / 0.00765765490875 = 27 / 0.00765765490875

l = 3525.8836 = 3526 ft. = 39072 in.

Where am I correct?

Guest

### Re: Length of Wire

Error in calculation;

0.0007669921875 = 27

0.0007669921875l / 0.0007669921875 = 27 / 0.0007669921875

l = 35202.44 in. = 2933.53705 = 2934 ft.

Guest

### Re: Length of Wire

$\frac{1}{32}*\frac{1}{32}*pi*l = 27$
l=27*32*32/pi

Guest

### Re: Length of Wire

l= 27 * 32 * 32/pi

l = 86858.9568 = 86859 ft. = 1042308 in.

What part is correct?

Guest


text:
4 added 50 characters in body

I want to create a fractal, which looks like this:

This is rule 150R, which can be found in NKS, page 458NKS, page 439.

However, instead of using a cellular automaton, I want to create this fractal from a single element like this (here the first three steps are shown):

Is it possible to do it for 5-10 steps automatically? How can I do that?

It's easier to rotate the element, then it can be displayed like this:

Elm=Graphics[{Rectangle[{1,0},{3,1}],Rectangle[{0,1},{1,3}],Rectangle[{3,1},{4,2}],Rectangle[{1,3},{2,4}],Rectangle[{2.5,2},{3,2.5}],Rectangle[{2,2.5},{2.5,3}]}]; Print[Elm]

Then I need to make several scaled down copies, rotate them and place then in the correct positions.

But I don't know how to do that efficiently (I don't know how to do that at all).

Except for rotation, which is simple since there are only 4 directions.

I want to create a fractal, which looks like this:

This is rule 150R, which can be found in NKS, page 458.

However, instead of using a cellular automaton, I want to create this fractal from a single element like this (here the first three steps are shown):

Is it possible to do it for 5-10 steps automatically? How can I do that?

It's easier to rotate the element, then it can be displayed like this:

Elm=Graphics[{Rectangle[{1,0},{3,1}],Rectangle[{0,1},{1,3}],Rectangle[{3,1},{4,2}],Rectangle[{1,3},{2,4}],Rectangle[{2.5,2},{3,2.5}],Rectangle[{2,2.5},{2.5,3}]}]; Print[Elm]

Then I need to make several scaled down copies, rotate them and place then in the correct positions.

But I don't know how to do that efficiently (I don't know how to do that at all).

Except for rotation, which is simple since there are only 4 directions.

I want to create a fractal, which looks like this:

This is rule 150R, which can be found in NKS, page 439.

However, instead of using a cellular automaton, I want to create this fractal from a single element like this (here the first three steps are shown):

Is it possible to do it for 5-10 steps automatically? How can I do that?

It's easier to rotate the element, then it can be displayed like this:

Elm=Graphics[{Rectangle[{1,0},{3,1}],Rectangle[{0,1},{1,3}],Rectangle[{3,1},{4,2}],Rectangle[{1,3},{2,4}],Rectangle[{2.5,2},{3,2.5}],Rectangle[{2,2.5},{2.5,3}]}]; Print[Elm]

Then I need to make several scaled down copies, rotate them and place then in the correct positions.

But I don't know how to do that efficiently (I don't know how to do that at all).

Except for rotation, which is simple since there are only 4 directions.

3 added 64 characters in body

I want to create a fractal, which looks like this:

This is rule 150R, which can be found in NKS, page 458.

However, instead of using a cellular automaton, I want to create this fractal from a single element like this (here the first three steps are shown):

Is it possible to do it for 5-10 steps at least automatically? How can I do that?

It's easier to rotate the element, then it can be displayed like this:

Elm=Graphics[{Rectangle[{1,0},{3,1}],Rectangle[{0,1},{1,3}],Rectangle[{3,1},{4,2}],Rectangle[{1,3},{2,4}],Rectangle[{2.5,2},{3,2.5}],Rectangle[{2,2.5},{2.5,3}]}]; Print[Elm]

Then I need to make several scaled down copies, rotate them and place then in the correct positions.

But I don't know how to do that efficiently (I don't know how to do that at all).

Except for rotation, which is simple since there are only 4 directions.

I want to create a fractal, which looks like this:

This is rule 150R, which can be found in NKS, page 458.

However, instead of using a cellular automaton, I want to create this fractal from a single element like this (here the first three steps are shown):

Is it possible to do it for 5-10 steps at least automatically? How can I do that?

It's easier to rotate the element, then it can be displayed like this:

Elm=Graphics[{Rectangle[{1,0},{3,1}],Rectangle[{0,1},{1,3}],Rectangle[{3,1},{4,2}],Rectangle[{1,3},{2,4}],Rectangle[{2.5,2},{3,2.5}],Rectangle[{2,2.5},{2.5,3}]}]; Print[Elm]

Then I need to make several scaled down copies, rotate them and place then in the correct positions.

But I don't know how to do that efficiently (I don't know how to do that at all).

I want to create a fractal, which looks like this:

This is rule 150R, which can be found in NKS, page 458.

However, instead of using a cellular automaton, I want to create this fractal from a single element like this (here the first three steps are shown):

Is it possible to do it for 5-10 steps automatically? How can I do that?

It's easier to rotate the element, then it can be displayed like this:

Elm=Graphics[{Rectangle[{1,0},{3,1}],Rectangle[{0,1},{1,3}],Rectangle[{3,1},{4,2}],Rectangle[{1,3},{2,4}],Rectangle[{2.5,2},{3,2.5}],Rectangle[{2,2.5},{2.5,3}]}]; Print[Elm]

Then I need to make several scaled down copies, rotate them and place then in the correct positions.

But I don't know how to do that efficiently (I don't know how to do that at all).

Except for rotation, which is simple since there are only 4 directions.

2 added 4 characters in body; edited title

# Creating I would like to create a fractal by copying, scaling and rotating the initial element

I want to create a fractal, which looks like this:

This is rule 150R, which can be found in NKS, page 458.

However, instead of using a cellular automaton, I want to create this fractal from a single element like this (here the first three steps are shown):

Is it possible to do it for 5-10 steps at least automatically? How can I do that?

It's easier to rotate the element, then it can be displayed like this:

Elm=Graphics[{Rectangle[{1,0},{3,1}],Rectangle[{0,1},{1,3}],Rectangle[{3,1},{4,2}],Rectangle[{1,3},{2,4}],Rectangle[{2.5,2},{3,2.5}],Rectangle[{2,2.5},{2.5,3}]}]; Print[Elm]

Then I need to make several scaled down copies, rotate them and place then in the correct positions.

But I don't know how to do that efficiently (I don't know how to do that at all).

# Creating a fractal by copying, scaling and rotating the initial element

I want to create a fractal, which looks like this:

This is rule 150R, which can be found in NKS, page 458.

However, instead of using a cellular automaton, I want to create this fractal from a single element like this (here the first three steps are shown):

Is it possible to do it for 5-10 steps at least automatically? How can I do that?

It's easier to rotate the element, then it can be displayed like this:

Elm=Graphics[{Rectangle[{1,0},{3,1}],Rectangle[{0,1},{1,3}],Rectangle[{3,1},{4,2}],Rectangle[{1,3},{2,4}],Rectangle[{2.5,2},{3,2.5}],Rectangle[{2,2.5},{2.5,3}]}]; Print[Elm]

Then I need to make several scaled down copies, rotate them and place then in the correct positions.

But I don't know how to do that efficiently (I don't know how to do that at all).

# I would like to create a fractal by copying, scaling and rotating the initial element

I want to create a fractal, which looks like this:

This is rule 150R, which can be found in NKS, page 458.

However, instead of using a cellular automaton, I want to create this fractal from a single element like this (here the first three steps are shown):

Is it possible to do it for 5-10 steps at least automatically? How can I do that?

It's easier to rotate the element, then it can be displayed like this:

Elm=Graphics[{Rectangle[{1,0},{3,1}],Rectangle[{0,1},{1,3}],Rectangle[{3,1},{4,2}],Rectangle[{1,3},{2,4}],Rectangle[{2.5,2},{3,2.5}],Rectangle[{2,2.5},{2.5,3}]}]; Print[Elm]

Then I need to make several scaled down copies, rotate them and place then in the correct positions.

But I don't know how to do that efficiently (I don't know how to do that at all).

1


text:
# Changes

## Element structure of dihedral group:D8

, 22:50, 21 June 2013
Interpretation as unitriangular matrix group
group = dihedral group:D8|
connective = of}}
{{fblike}}
We denote the identity element by $e$. The '''dihedral group''' $D_8$, sometimes called $D_4$, also called the {{dihedral group}} of order eight or the dihedral group acting on four elements, is defined by the following presentation:
$\langle x,a| a^4 = x^2 = e, xax^{-1} = a^{-1}\rangle$
Below is the
 The row element is multiplied on the left and the column element is multiplied on the right.
{{#lst:dihedral group:D8|multiplication table}class="sortable" border="1"!Element !! $\! e$ !! $\! a$ !! $\! a^2$ !! $\! a^3$ !! $\! x$ !! $\! ax$ !! $\! a^2x$ !! $\! a^3x$|-| $\! e$ || $\! e$ || $\! a$ || $\! a^2$ || $\! a^3$ || $\! x$ || $\! ax$ || $\! a^2x$ || $\! a^3x$|-| $\! a$ || $\! a$ ||$\! a^2$ || $\! a^3$ ||$\! e$ || $\! ax$ || $\! a^2x$ || $\! a^3x$ || $\! x$|-| $\! a^2$ || $\! a^2$ || $\! a^3$ ||$\! e$ ||$\! a$ ||$\! a^2x$ || $\! a^3x$ || $\! x$ || $\! ax$|-| $\! a^3$ || $\! a^3$ ||$\! e$ ||$\! a$ ||$\! a^2$ ||$\! a^3x$ || $\! x$ || $\! ax$ || $\! a^2x$|-| $\! x$ || $\! x$ || $\! a^3x$ || $\! a^2x$ || $\! ax$ || $\! e$ || $\! a^3$ || $\! a^2$ || $\! a$|-| $\! ax$ || $\! ax$ || $\! x$ || $\! a^3x$ || $\! a^2x$ || $\! a$|| $\! e$ || $\! a^3$ || $\! a^2$|-| $\! a^2x$ || $\! a^2x$ || $\! ax$ || $\! x$ || $\! a^3x$ || $\! a^2$ || $\! a$ || $\! e$ || $\! a^3$|-| $\! a^3x$ || $\! a^3x$ || $\! a^2x$ || $\! ax$ || $\! x$ || $\! a^3$ || $\! a^2$ || $\! a$ || $\! e$|}

{{quotation|'''CAUTION''': You may be looking instead for [[dihedral group:D16]], the dihedral group of ''degree'' 8 and order 16. If so, see [[element structure of dihedral group:D16]].}}
|}

==Commutator map==

Because of the fact that the [[inner automorphism group]] is an elementary abelian 2-group, it does not matter which of the two definitions of commutator map we choose ($[\alpha,\beta] = \alpha^{-1}\beta^{-1}\alpha\beta$ or $[\alpha,\beta] = \alpha\beta\alpha^{-1}\beta^{-1}$) -- they are both the same map.

In fact, the commutator map sends a pair of elements to $e$ if they commute and to $a^2$ if they don't commute.
{| class="sortable" border="1"
!Element !! $\! e$ !! $\! a$ !! $\! a^2$ !! $\! a^3$ !! $\! x$ !! $\! ax$ !! $\! a^2x$ !! $\! a^3x$
|-
| $\! e$ || $\! e$ || $\! e$ || $\! e$ || $\! e$ || $\! e$ || $\! e$ || $\! e$ || $\! e$
|-
| $\! a$ || $\! e$ || $\! e$ || $\! e$ || $\! e$ || $\! a^2$ || $\! a^2$ || $\! a^2$ || $\! a^2$
|-
| $\! a^2$ || $\! e$ || $\! e$ || $\! e$ || $\! e$ || $\! e$ || $\! e$ || $\! e$ || $\! e$
|-
| $\! a^3$ || $\! e$ || $\! e$ || $\! e$ || $\! e$ || $\! a^2$ || $\! a^2$ || $\! a^2$ || $\! a^2$
|-
| $\! x$ || $\! e$ || $\! a^2$|| $\! e$ || $\! a^2$||$\! e$ || $\! a^2$||$\! e$ || $\! a^2$
|-
| $\! ax$ || $\! e$ || $\! a^2$ || $\! e$ || $\! a^2$ || $\! a^2$|| $\! e$ || $\! a^2$ || $\! e$
|-
| $\! a^2x$ || $\! e$ || $\! a^2$|| $\! e$ || $\! a^2$||$\! e$ || $\! a^2$||$\! e$ || $\! a^2$
|-
| $\! a^3x$ || $\! e$ || $\! a^2$ || $\! e$ || $\! a^2$ || $\! a^2$|| $\! e$ || $\! a^2$ || $\! e$
|}

==Conjugacy class structure==
{{conjugacy class structure facts to check against}}

===General description===

| $\! \{ ax, a^3x \}$ || reflections about lines joining midpoints of opposite sides || $\{ (1,4)(2,3)\ , \ (1,2)(3,4) \}$ || 2 || 2 || $\{ e, a^2, ax, a^3x \}$ -- one of the [[Klein four-subgroups of dihedral group:D8]]
|-
| $\! \{ a, a^3 \}$ || rotations by odd muliples multiples of $\pi/2$ || $\{ (1,2,3,4) \ ,\ (1,4,3,2) \}$ || 2 || 4 ||$\{ e, a, a^2, a^3 \}$ -- the [[cyclic maximal subgroup of dihedral group:D8]]
|-
| Total (5)|| -- || -- || 8 || -- || --

===Interpretation as dihedral group===

{{quotation|Compare with [[element structure of dihedral groups#Even degree case]]}}

Below, we consider the conjugacy class structure in terms of the interpretation ofthe group as a dihedral group of degree $2n$, where $n = 4$ is even:

{| class="sortable" border="1"
! Conjugacy class type !! Size of conjugacy class (generic even $n$) !! Size of conjugacy class ($n = 4$) !! Number of conjugacy classes of this type (generic even $n$) !! Number of conjugacy classes ($n = 4$) !! Total number of elements (generic even $n$) !! Total number of elements ($n = 4$) !! Actual list of conjugacy classes
|-
| Identity element || 1 || 1 || 1 || 1 || 1 || 1 || $\{ e \}$
|-
| Non-identity element $a^{n/2}$ of order two in $\langle a \rangle$ || 1 || 1 || 1 || 1 || 1 || 1 || $\{ a^2 \}$
|-
| Non-identity elements in cyclic group $\langle a \rangle</matH>, where each element and its inverse form a conjugacy class of size two || 2 || 2 || [itex](n - 2)/2$ || 1 || $n - 2$ || 2 || $\{ a, a^3 \}$
|-
| Elements outside $\langle a \rangle$, form two conjugacy classes, one for elements of the form $a^{2k}x$, one for elements of the form $a^{2k+1}x$ || $n/2$ || 2 || 2 || 2 || $n$ || 4 || $\{ x, a^2x \}, \{ ax, a^3x \}$
|-
! Total (--) !! -- !! -- !! $(n + 6)/2$ !! 5 !! $2n$ !! 8 !! --
|}

===Interpretation as unitriangular matrix group===

{{quotation|Compare with [[element structure of unitriangular matrix group of degree three over a finite field#Conjugacy class structure]]}}

We view the dihedral group of order eight as a [[unitriangular matrix group of degree three]] over [[field:F2]], which is the group under multiplication of matrices of the form:

$\begin{pmatrix} 1 & a_{12} & a_{13} \\ 0 & 1 & a_{23} \\ 0 & 0 & 1 \\\end{pmatrix}$

with the entries over the field of two elements. We compare with the general theory of the conjugacy class structure of the group $UT(3,q)$, where <matH>q</matH> is the field size. We denote by $p$ the prime number that is the characteristic of the field, so <matH>q[/itex] is a power of $p$.

Note that the letter $a$ used for matrix entries has no direct relation to the letter $a</matH> used for group elements of [itex]D_8$.

{| class="sortable" border="1"
! Nature of conjugacy class !! Minimal polynomial !! Size of conjugacy class (generic $q$) !! Size of conjugacy class ($q = 2$) !! Number of such conjugacy classes (generic <matH>q[/itex]) !! Number of such conjugacy classes ($q = 2$) !! Total number of elements (generic $q$) !! Total number of elements ($q = 2$) !! List of conjugacy classes !! Order of elements in each such conjugacy class (generic $q$) !! Order of elements in each conjugacy class ($q = 2$) !! Type of matrix
|-
| identity element || $t - 1$ || 1 || 1 || 1 || 1 || 1 || 1 || $\{ e \}$ || 1 || 1 || $a_{12} = a_{13} = a_{23}= 0$
|-
| non-identity element, but central (has Jordan blocks of size one and two respectively) || $(t - 1)^2$ || 1 || 1 || $q - 1$ || 1 || $q - 1$ || 1 || $\{ a^2 \}$ || $p$ || 2 || $a_{12} = a_{23} = 0$ $a_{13} \ne 0$
|-
| non-central, has Jordan blocks of size one and two respectively || $(t - 1)^2$ || $q$ || 2 || $2(q - 1)$ || 2 || $2q(q - 1)$ || 4 || $\{ x, a^2x, \}, \{ ax, a^3x \}$ || $p$ || 2 || $a_{12}a_{23} = 0$, but not both $a_{12}$ and $a_{23}$ are zero
|-
| non-central, has Jordan block of size three || $(t - 1)^3$ || $q$ || 2 || $(q - 1)^2$ || 1 ||$q(q - 1)^2$ || 2 || $\{ a, a^3 \}$ || $p$ if $p$ odd
4 if $p = 2$ || 4 || both $a_{12}$ and $a_{23}$ are nonzero
|-
! Total (--) !! -- !! -- !! -- !! $q^2 + q - 1$ !! 5 !! $q^3$ !! 8 !! -- !! -- !! -- !! --
|}

===Convolution algebra on conjugacy classes===


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Numerical Methods: Integration of given function using Simpson’s 3/8 rule in C

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text:
# Gene Cluster Discovery

CREATED: 200701031149

see tag #gene_cluster

** Ideas

• given GTT for n and another gene order, compute GTT for n+1
• models for gap + seq, CI with errors (median clusters)
• using ideas from data mining, freq item set mining, clustering (see Clustering based Gene Cluster Discovery)
• Domain teams - PFAM, HMMER (threshold 10^-3)
• Can He2004 be extended to multiple sequences? ** Compute gene teams for all pairs of genomes? ** From $G_1$ to $G_i$ for all i?
• Maximal density based gene clusters? density is at least #points/length in each seq
• find out about Didier’s algorithm
• PQ-trees, relation to strong intervals (Bergeron), $\pi$-patterns (Landau)
• use frequent itemset for conserved gene clusters

## find frequent item sets using data mining methods - complexity of frequent itemset mining

• score function (properties of score function)
• Integer linear programming approach by Rahmann, S., Klau, G. W ** Hon Wai has contacts with Dr Klau
• Is the conservation of order in a cluster important?
• For gap between two markers, does it matter if there is nothing in this gap or the gap is filled with genes?
• develop algorithms which take into account statistical significance of clusters
• gene team on seq is quite slow, can this be improved?
• gene team, compute base on p-value
• r-window clusters - statistics, algorithms
• more efficient algorithms for common cluster models
• develop new cluster models
• combine statistical measure with discovery

** Formulation

• Given a set of genomes (gene order), find all conserved gene clusters
• similar to motif finding but on the level of genes instead of nucleotides
• usually do not take into account order of genes

** Homology

• common ancestor
• practical definition ** sequence similarity ** context - surrounding markers ** expression/regulation

** Markers

• proteins
• domains

Relationship between markers

• interaction

** Gene Clusters EC operons is one kind of conserved gene cluster. Q: how well does the gene team “model” operon clusters? A: Determine number of teams that correspond to operons for single value of delta and over all delta (GTT). Pairwise comparison and multiple gene orders (show practicality and scalability of GTT for more than 2 gene orders)

Q: how well does gene team “model” conservation in multichromosomal genomes (human/mouse)? A: what are analog to operons in eukaryotes? synteny blocks?


text:
doc-src/Intro/getting.tex
 changeset 1878 ac8e534b4834 parent 331 13660d5f6a77 child 3103 98af809fee46
--- a/doc-src/Intro/getting.tex	Mon Jul 22 16:15:45 1996 +0200
+++ b/doc-src/Intro/getting.tex	Mon Jul 22 16:16:51 1996 +0200
@@ -591,7 +591,7 @@
Let us contrast a proof of the theorem $\forall x.\exists y.x=y$ with an
attempted proof of the non-theorem $\exists y.\forall x.x=y$.  The former
proof succeeds, and the latter fails, because of the scope of quantified
-variables~\cite{paulson89}.  Unification helps even in these trivial
+variables~\cite{paulson-found}.  Unification helps even in these trivial
proofs. In $\forall x.\exists y.x=y$ the $y$ that exists' is simply $x$,
but we need never say so. This choice is forced by the reflexive law for
equality, and happens automatically.
@@ -668,7 +668,7 @@
\end{ttbox}
There can be no proof of $\exists y.\forall x.x=y$ by the soundness of
first-order logic.  I have elsewhere proved the faithfulness of Isabelle's
-encoding of first-order logic~\cite{paulson89}; there could, of course, be
+encoding of first-order logic~\cite{paulson-found}; there could, of course, be
faults in the implementation.

`


text:
# Leonid Gurvits's Proof of the Van der Waerden Conjecture

Speaker:

## Time:

Friday, 19 July 2013, 14:30 to 16:00

## Venue:

• A-212 (STCS Seminar Room)

## Organisers:

The permanent of a doubly stochastic matrix is at least that of the matrix with each entry $1/n$ (the matrices are $n x n$). This theorem, popularly known as the 'Van der Waerden conjecture', remained open for over fifty years, before it was finally proved  by Falikman (1979) and Egoritsjev (1980). Relatively recently, in 2008, Leonid Gurvits gave an amazingly short proof for it. In this talk, we will discuss this new proof.


text:
A 3.00 kg particle has the xy coordinates (-1.20 m, 0.500 m) and a 5.00 kg particle has the xy coordinates (0.600 m, -0.750 m). Both lie on a horizontal plane. At what (a) x and (b) y coordinates must you place a 5.00 kg particle such that the center of mass of the three-particle system has the coordinates (-0.500 m, -0.700 m)?
(a) x coordinate
m

(b) y coordinate
m


text:
2 What Is Velocity Of Ground With Respect To B

2 What Is Velocity Of Ground With Respect To B0 $$\hat{k}$$ m/s, and the velocity of reference frame B with respect to C is 2. A spectator is moving with a speed of -15m/s with regards to the …. A cannonball is shot (from ground level) with an initial horizontal velocity of 41 m/s and an initial vertical velocity of 23 m/s. (a) Briefly describe the motion of the beam represented by AB, BC, CD and DE. Average Velocity and Average Acceleration A canoeist paddles upstream at 2 m/s and then turns around and floats downstream at 4 m/s. The projectile travels with the same speed at point B …. Velocity of an object is given as: V(t)=t^2 -t-12 a) determine the total distance traveled between 1 and 5 seconds b) determine the average velocity between 2 …. If i ignore someone on messenger can they see my story. Given the formula for the orbital velocity, v = 2πr Torbit = r gR2 e r a rate of coverage can be calculated by rate of coverage = v · Re r ·w where w is the swath width (see also Figure 2). 20 N in the direction opposite to the velocity (B) 30 N in the direction opposite to the velocity …. magnitude of the horizontal component of velocity as the rock strikes the ground? a. The vector equation is →v PG = →v PA + →v AG, v → PG = v → PA + v → AG, where P = plane, A = air, and G = ground. Muon Decay: Time Dilation (\Moving Clocks Run Slow") Problem 1. → is the velocity of the Man relative to the Train, v → T ∣ E {\displaystyle {\vec {v}}_{T\mid E}} is the velocity of the T rain relative to E arth. From what height ( h ) should an another particle ( B ) be projected horizontally with velocity ( 5 mathrm{m} / mathrm{s} ) so that both the particles collide in ground …. Q: If you are walking at constant velocity of 8 km/h and a car passed you by at the speed of 30 km/h from behind, what is the car's velocity from your viewpoint? A: 22 km/h. The gradient of a velocity-time graph is acceleration 10 5-5-10 v (ms ) t (s) 0. What is the acceleration of a baseball thrown to the air at an angle of 45 degrees with respect to the horizontal as it returns to the ground? A. Projectile Motion Without Initial Velocity. Suppose the tourist in question #1 instead threw the rock with an initial velocity of 8. velocity of a with respect to b + velocity of b with respect to c. D) increase the amplitude of the wave by a factor of 8. t ground = v Velocity of the image in the mirror w. The significance of the negative velocity is that the rate of change of the distance with respect to time (velocity) is negative because the distance is decreasing as the time increases. Displacement is the shortest distance from the initial to the final position of the object, which is not the same as distance travelled because it is the length of an imaginary straight path. Action reaction and momentum conservation answer key pdf the physics classroom. V AB is the velocity with respect to A and B, V BC is the velocity with respect to B and C and V AC is the velocity with respect to A and C. E) increase the amplitude of the wave by a factor of 2. Relative to O, the position vector of a point on the path of P is (xi + yj) m. Using the quadratic to find the zeros, so I can find at what time the ball hits the ground. v m,g = v m,A + v Ag = 18 - 54 = -36 km/h Hence, velocity of monkey will be 36 km/h toward north. It's not actually moving with respect to the ground…. In this frame, the bottom of the wheel has velocity -v, while the top of the wheel has velocity v. Answer: (a) 13 m/s2; (b) eastward; (c) 13 m/s2; (d) eastward вЂў70A boat is traveling upstream in the positive direction of an x axis at 14 km/h with respect to the water of a river. Its kinetic energy when reaching the ground will be ½mv 2 = 2mgR. The magnitude of the average velocity is : a) 3. a) The relative velocity to the airplane A respect airplane B. Acceleration is a vector quantity that repre-sents the time-rate of change in ANSWER: (2) velocity …. Suppose a boy is enjoying a ride on a merry-go-round which is moving with a constant speed of 10 ms -1 It implies that the boy is. How to reset service b light on 2007 acura tl. V A = is the velocity in reference to A. Find out the benefits of B vitamins. Final velocity (v) = 100 km/s = 100 x 103 m/s. Average velocity is zero for the whole process. For example, the binary function. V AB = the velocity in reference to A and B, V B = the velocity with reference to B. This means that you can determine the height it travels before starting its decent by using the initial velocity. 2), the velocity of airplane A with respect …. Particles with this velocity will go through undeflected. The vertical component of velocity is of course down, but the magnitude is the same. A thin uniform rod is supported by a vertical string and by a hinge h. Answer C is wrong because the distance increases every second. two different frames of reference while measuring the relative velocity of . Most radars can measure reflectivity but you need a Doppler radar to measure velocity. Because of this, we can apply the same trigonometric rules to a velocity vector magnitude and its components, as seen below. (II) Two locomotives approach each other on parallel tracks. that we are making measurement from the moving frame (reference) of "B". A sailboat is on a heading of due East at 5 m/s while . A boy on the elevator shoots a ball directly upward, from a height of 2. What is the average velocity …. The time for projectile motion is determined completely by the vertical motion. Relative Velocity Formula - Definition, Formu…. However, player B hits the ball when it is 1. Suppose the tourist in question #1 instead threw the rock with an initial velocity …. A block is released from rest and slides down a frictionless ramp inclined at 30. Determine the magnitude v of the velocity …. The ball is caught by the receiver 2. An airplane that flies at 100 km/h with a 10 km/h tailwind travels at 110 km/h relative to the ground. Calculate the momentum (in kg m/s) of the ostrich. 5 m with respect to the launch position. And finally we're given the information that the plane, the velocity of the plane, the magnitude of the loss of a planet with respect to air as 70 kilometers per hour. The terminal velocity for a skydiver was found to be in a range from 53 m/s to 76 m/s. is the difference in the speeds of body A and body B. After reaching the other end, the man turns back and continues running with 3v velocity with respect to trolley in opposite direction. a man cycling with speed 20kmph in A to B direction . Determine 1) Velocity and acceleration after 4 sec. 2JPart iiConservation of energy states that the sum of the GPE and KE at the intial position is equal to the sum of the GPE and KE at the final position. A ball is dropped from a height of 80cm after each bounce it rebounds to 70. What is the approximate potential energy of the mass with respect to the ground? a. It will take the passenger 18 s to walk a distance of 27 m on the ship. The relative velocity of B with respect to A, V BA = 80 km h −1 due west. The values of and are given in the statement of the problem. Our initial and final speed calculator of physics also helps you to calculate both the initial and final speed of an object. The velocity of a body with respect to the velocity of another body is called the relative velocity of the first body with respect to the second. Their symptoms may be similar, but they differ largely in how they're transmitted from person to person. The general gravity equation for the velocity with respect to time is: v = gt + v i. Then add this number to your measurement from step 6. t = v Image and object both are moving towards each other so relative velocity …. A ball kicked from ground level at an initial velocity of 60 m/s and an angle θ with ground …. · Ground Speed · Airspeed · Examples. Find the rate of increase of the surface area with respect to the radius r when r is each of the following. A projectile is fired from the ground level with an initial velocity v 0. So, the relative velocity of train. If you know 2 of the 3 variables the third can be calculated. the x-velocity is non-zero, but the y-velocity is zero d. Your velocity with respect to the shore is your velocity relative to the ferry plus the ferry's velocity relative to the shore: m/s south + 7. (15) with respect to and setting it equal to zero: or Ground Lift Coefficient for Minimum Takeoff Ground Run Distance (16) Example 2. Determine: a) the time of flight (5) b) the range of the projectile (5) c) the maximum height above the ground (5) d) the components of vx and vy when the projectile strikes the ground (5) e) the magnitude of the velocity and angle the velocity vector makes with respect to the ground just as the projectile lands (10). Its direction is currently straight toward the top of a mountain. Example 3: A missile is accelerating at a rate of 4 t m/sec 2 from a position at rest in a silo 35 m below ground level. It is typically stated as an ideal speed, ignoring atmospheric friction. 8 m/s, Dy=h=15 m, and v 1=0 yields t = 2 h g = 2*15 m 9. So the velocity of the plane relative to the ground is 292. Turn diameter is 1% of the speed. ) What is the magnitude of the ball's velocity after 2. !AfricanAmericans!were!unable Dec 27, 2017 · APUSH Short Answer Questions: Question 1. Samacheer Kalvi 7th Science Solution Question 3. Example What is the velocity of the B with respect to A? V²BA=V²B+V²A. An elevator without a ceiling is ascending with a constant speed of 10 m/s. Therefore, cart B appears to move from South to North with a speed of 70 ms-1 for any person sitting in cart A. has a known velocity in the frame of (with respect to) a medium like air or water which itself is moving with respect to the stationary ground; we can then ﬁnd the velocity of the plane or boat with respect to the ground from the vector sum in Eq. b) Velocity of B with respect to A. A boat is traveling upstream at 11 km/h with respect to the water of a river. The angular velocity of Earth is 360 degrees per day, or. f ( x , y ) = x 2 + y 2 {\displaystyle f (x,y)=x^ {2}+y^ {2}} has two arguments, x {\displaystyle x} and. cylinder that is in contact with the string with respect to the string--it should be zero. Calling east the positive direction, you know …. What is the velocity of the ball when it hit's the ground (Height 0)? calculus. The velocity of the ball is also a function of time:. Multiply this measurement by the total number of times you walked across the floor. 80 meters per second multiplied by 2. Graphing motion virtual lab 2 answers. A block is thrown with a velocity of 2 ms–1 (relative to ground) on a belt, which is moving with velocity 4 ms–1 in opposite direction of the initial velocity of block. Question 1044696: A football is kicked at an angle of 37 degrees with a velocity of 20 m/s. The density of the substance (in g cm 3) with the correct number of significant figures is. When the arrow hits the ground at the same height it was shot the magnitude of its final velocity is the same as that of its initial velocity. It describes the velocity of an object with respect to the other object at rest . average velocity = 30 1/2 - 1/2 average velocity of the balloon between t = 0 and t = 30 = 30 ft/sec c) Velocity is the change of displacement of a body with respect to time. Using trigonometry, the direction of this velocity is tan-1 (1. As it falls back to the ground…. b) If the bottle were more massive, how would this affect the final velocity of the ball? Answer: a. Displacement is measured in units of length, such as meters. A particle A is projected from the ground with an initial velocity of 10 m/s at an angle $60 ^{\circ}$ with horizontal. Example 11 Crossing a River The engine of a boat drives it across a river that is 1800m wide. the relative velocity of the ground with respect to B? c. For a reference point picked on the ground, the air moves relative to the reference point at the wind speed. The velocity of the particle at the end of 2 seconds. The velocity of reference frame A with respect to reference frame B is 4. Clay Matthews, a linebacker for the Green Bay Packers, can reach a speed of 10. 81 m/s² Nov 24, 2015 — A ball is thrown vertically upwards with a speed of 18. 0 m below its starting altitude spends 3. Initially, u perpendicular to v and separation was l. Velocity of an object is given as: V(t)=t^2 -t-12 a) determine the total distance traveled between 1 and 5 seconds b) determine the average velocity between 2 and 10 seconds View Answer A ball is. • v is the velocity of a point on the object with respect to the axis of rotation. If the initial velocity of the bike Is 4. 0 s of its motion? If the rock hits the ground after 2. Which of the following is true for the whole process. (B) The coefficient of restitution is 0. In the simplest kind of projectile motion problems, there is no initial velocity. The rocket hits the ground at height h = 0. This concept of velocity may be extended to find the rate of change of any variable with respect …. If block A shown in figure is moving with speed v as observed by a person on ground then the magnitude of velocity of A with. If we say that g = 10 m/s 2, therefore, we mean that the velocity of the falling object changes by 10 m/s each second that it falls. At time t2 = 57 min, the dog’s displacement from the station is 2. Continue Practice Exam Test Questions Part II of the Series.  I guess it's because of the new Season 9 update, but there's a majorly game impacting bright purple flickering happening in the lobby and when I'm in a match on the ground…. b) State and prove the law of conservation of …. A car accelerates from rest and reaches a velocity of 6 ms after 2 seconds. Since the person is walking west, in the negative direction, we write her velocity with respect to the train as v → P T = −2 m/s i ^. The airspeed is then given by: Airspeed = Ground Speed (80) - Wind Speed (20) = 60 mph This airplane doesn't have enough airspeed to fly. The velocity of the person is the velocity of the speeding train plus the velocity of the jump out. is displacement, is the final position, and. So the velocity of air with respect of ground and magnitude off this is given to us is 20 kilometers per hour. A quarterback throws a pass at an angle of 40 degrees above the horizontal with an initial speed of 20 m/s. The distance traveled downstream is d = v • t = (7 m/s) • (20 s) = 140 m. 9 t 2 + 49 t + 15 gives the height in meters of an object after it is thrown vertically upward from a point 15 meters above the ground at a velocity …. to hit the ground? (b) If the plane has an air speed of 8 km/h, what is the horizontal distance that the wheel travels before it hits the ground. If the river is flowing with a velocity of 2. Call the velocity of the turtle with respect to the ground v TG, also known as v 2. A tennis ball is thrown off a cliff 10 m above the ground with an initial horizontal velocity of 5 m/s as shown above. Because the change in position is the displacement, we can express the average velocity as:. An airplane's velocity with respect to the air is 580 miles per hour, and it is heading N 60 degrees W. Using the Law of Addition of Velocities, Equation (11. Big Data could be 1) Structured, 2) Unstructured, 3) Semi-structured. Two boathouses are located on a river, 1. dx/dt = d/dt 4t 2 + 4t + 4 = v (t) Step 2…. Radar output generally comes in two forms: reflectivity and velocity. What is the velocity of block B as it touches the ground? How far will block A travel if the coefficient of friction between block A and the surface is 0. (d) the velocity of the object between t = 90 s and t = 100 s. You also know the velocity of the man with . (d) Velocity of monkey as observed by a passenger of train B. Velocity of contact point Find a general expression for the velocity of the point of contact. The setup is the same as the previous problem except that there is a force due to air resistance of magnitude v2=1325 directed opposite to the velocity, where the velocity …. Now while calculating the difference between V1 and V2, we will use the vector addition process but with a tweak. (b) We can find the final horizontal and vertical velocities. Using s = ut + at 2 /2 for change in vertical distance in time t, with acceleration a (-9. (b) Determine the magnitude and direction of the wind's velocity. Putting these values in third equation of motion v 2 = u 2 + 2 a s we have. An ostrich with a mass of 146 kg is running to the right with a velocity of 17 m/s. Find an answer to your question A boat is moving with a velocity 3i + 4j with respect to the ground. I'm not sure how to find the velocity though. At the end of the ground run, the velocity …. 0 m/s due north relative to the air mass, while its velocity relative to the ground (its total velocity) is 38. A car goes 78 m to the righty and then 22 m to the left. Use Figure (2) to find (a) the velocity of the object during the first 40 s. ± means plus or minus; √(2gy + v i 2) is the square root of the quantity (2gy + v i 2) y is the vertical displacement in meters (m. Determine the directional angle relative to due south. Calculate the (a) relative velocity of ground with respect to B (b) relative velocity of A with respect to B. with the use of the result from (a). Average muzzle velocity 920fps. Acceleration implies any change in the velocity of the object with respect to time. Hint: When objects fall to the ground, gravity causes them to accelerate. Divide this product by the time period. At a particular instant, a house is directly below the plane at ground …. H = V 02 / (2 g) 2) Velocity …. Time can't be negative, therefore the ball htis the ground at 8. The velocity of a particle in reference frame A is (2. The acceleration of the particle at the end of 2 seconds. Although the term "escape velocity…. What is the new angular velocity of the platform? (A) ( +2 )𝜔𝑅−2 𝑣 𝑅 (B) ( −2 )𝜔𝑅−2 𝑣 𝑅 (C) ( +2 )𝜔𝑅+2 𝑣 𝑅 (D) ( +2 )𝜔𝑅−2 𝑣 𝑅 (E) ( +2 )𝜔𝑅−2 𝑣. b) Relative velocity of ground with respect to B = 0 – V B = 0 …. It explains the concept of the frame of reference and how it's used to determine the relative velocity of an object with another regardless if . A plane flying horizontally above Earth’s surface at 100. It’s here: V1-V2 = V1 + (-V2). Once you've plugged in the mass and velocity, you can solve for kinetic energy (KE). 0 seconds? What is the horizontal and vertical velocity …. An airplane of mass 10,000 kg is flying over level ground at a constant altitude of 4. If a coin is pushed horizontally from a 1. ) What is the angular velocity it is rolling at when it reaches the ground…. Determine the velocity and displacement of the rock at 4. Vst=Vs-Vt => Vst=2- (-50) <=> Vst=2…. Thus the velocity of the passenger. At a certain instant, a point P on its rim has a velocity whose x and y component are 120 in. Assessing velocities involves vector addition and a useful approach to such relative velocity problems is to think of one reference frame as an "intermediate" reference frame in the form:. What is Sam's velocity relative to the ground? (35. Feb 3, 2020 — Acceleration is a constant for a ball thrown vertically upward, its is acceleration due to gravity. If two bodies are moving in the same direction at the same velocity, then the relative velocity will . 0 m/s, how far does it travel in 3 s? (A) 2. Although the circular trajectory of ladybug 2 has twice the radius as that of ladybug 1, ladybug 2 also has twice the linear velocity of ladybug 1. How high above the ground will it be. Find the force exerted by B and C by pushing the crates to the right with an acceleration of 1. Then, select the option for which you want to perform calculations, it can either “velocity, time, or distance”. 81 m/s 2 (or or 32 ft/s 2) for every second it experiences. Say the actual velocity of the object is V1 and the actual velocity of the viewer is V2. A falling object is acted on by the force of gravity: -9. 8 metres per second squared (m/s 2). 4 X 10 8m/s c) 3 x 10 8m/s d) 2. 5-kg sprinter exerts a force of 775 N on the starting block which is on a 20. A distance—time graph for a bicycle travelling down a hill. An onlooker is moving at a speed of -25m/s with respect to the. Two objects (A and B) are moving with velocity V A and V B. The average velocity that the car traveled was 14. The trajectory of a projectile launched from ground is given by the equation y = -0. Where the following additional variables are introduced: V rel is the horizontal velocity of point P (on the wheel) relative to point O a rel is the horizontal acceleration of point P (on the wheel) relative to point O Therefore, by vector addition the velocity of point P with respect to the surface/ground …. (c) the velocity of the object between t = 70 s and t = 90 s. 8 m/s 2 or 32 ft/s 2) t is the time in seconds (s) that the object has fallen; Velocity of a falling object as a function of time or displacement. In (c), let the velocity of the monkey with respect to ground be vM. Find the velocity of the man with respect to the ground. A small ball falling vertically down with velocity 2 m/s strikee elastically an inclined plane moving with velocity 2 m/s. (b) The flea's trajectory must be a parabola as shown. C) Its vertical velocity component is the same as it was just as it was launched. (c) False, total path length can also be …. What are (a) the magnitude and (b) the direction of the boat's velocity with respect to the ground? A child on the boat walks from front to rear at 5. Now, let us tells you about the difference between velocity and speed with respect to 'Average. Truck A is moving 15 m/s E with respect to the ground, while Truck B is moving 18 m/s W relative to the ground. 9x19mm / 9mm Luger 115 Grain TMJ RN “Range Grade” Ammunition. The relative velocity of B with respect to. v ( t) = s ′ ( t) = 6 t + 8 − 5 t 3 2 v (t)=s. Calculate: a) The relative velocity to the airplane A respect airplane B. Of the five kinematic quantities listed here (distance, displacement, speed, velocity and acceleration), three of them are vectors. (a) Find the velocity of the rain with respect …. ) When will the ball hit the ground below? d. If you’re riding in a train moving at 10 m/s east, this velocity is measured relative to the ground …. 0 m/s What would be the velocity of the passenger For any two objects, A and B, the velocity …. 8 m/s, directed at an angle of 56° above the horizontal. It is facing a headwind of 5m/s with respect to the ground. Using the Pythagorean theorem, the resultant velocity can be calculated as, R 2 = (100 km/hr) 2 + (25 km/hr) 2 R 2 = 10 000 km 2 /hr 2 + 625 km 2 /hr 2. These require the relative velocity of spaceship B with respect to A, which we first find using Lorentz velocity addition: 2 B A A B 2 c v v 1 v v u' c v 1 u' v u + + = + + = where u = velocity of. What is the child's velocity with respect to the ground? a) 5 km/h "upstream" b) 1 km/h "downstream" 2) A person walks up a stalled 15-m-long escalator. Which one of the following 20. Crawler crane ground bearing pressure calculation excel. #underbrace(v_"top"^2)_(color(blue)("=0")) = v_i^2 - 2 …. To find velocity, we take the derivative of the original position equation. (a)True, because magnitude is a pure number. The roadway of this bridge is 70. Acceleration at maximum height is 9. g is the acceleration due to gravity (9. Choose the letter of the best answer in each questions. Since the person is walking west, in the negative direction, we write her velocity with respect to the train as. An Amber light indicates a low or critically low battery, and a Red light indicates the battery is dead and needs to be charged for at least 6 hours. Here's how to win: Enter in 3⃣ ways (choose any or all for more chances to win): 1⃣ Like this post, tag 2 …. is the change in position of an object: where. What are the (c) magnitude and (d) direction of the child's velocity with respect to the ground?. Find the velocity of the ant with respect to the: A)boat B)water. An import ant concept emerges from the analysis of the two example problems above. 2m/s Sign "-" means that ball is falling down. Note that car B has no acceleration. It remains at this velocity for I second and then accelerates again for 3 seconds to a final velocity of 10 ms At this point it brakes to a stop, taking 3 seconds to do so- (a) Graph the velocity-time graph of this journey on the grid below. Using the velocity addition rule, the relative motion equation we are seeking is. The 250-lb concrete block A is released from rest in the position shown and pulls the 400-lb log up the 30° ramp. 4 Two position vectors are drawn from the center of Earth, which is the origin of the coordinate system, with the y-axis as north and the x-axis as east. These types of problems can all be solved by knowing the relationship between the position, velocity, and acceleration equations. Find the actual ground speed and direction of the airplane. What is the (a) relative velocity of B with respect to A? (b) relative velocity of ground with respect to B ? and (c) velocity of a monkey running on the . Thus, according to the formula , where is centripital acceleration, ladybug 2 has twice the centripetal acceleration of ladybug …. This 9mm Luger ammo has a muzzle velocity …. The low velocities of ground-water flow can have important implications, particularly in relation . The acceleration along the ground is the same, so at 5000 feet down the runway, the ground speed is again 80 mph. Gravity causes an object to fall toward the ground at a faster and faster velocity the longer the object falls. In contrast to part (a), there now is a horizontal component of the velocity. 2 (2/2) You are traveling on an airplane. If two cars A and B are travelling on a straight road in opposite direction with velocity 4 5 m/s and 3 5 m/s then relative velocity of car A with respect to car B is. Example 13: Level Horizontal Range. The velocity of A with respect to B is: V A / B = V A − V B. A paint ball is fired straight up from ground level at 91. 0 m/s in a direction west of north. Suddenly a man star running from rear end of the trolley. Problem 1: A train travels with a speed of 70m/s with regards to the ground in the east direction. 5% of total body mass, and the length of the thigh is 23. Two parallel rail tracks run north - south. b) The relative velocity to the airplane A respect airplane B, but now both fly to the north. EVENT 2 x x' B 0 0' vA vB L 2L-L 2L vA and vB are measured w. In mathematics, an argument (also known as input) of a function is a value that must be provided to obtain the function's result. Plug in h = 0 or or The rocket is on the ground at or seconds. Question 2: A car moving with a velocity …. 2-D motion: In 2-D, the angular velocity …. The object's kinetic energy at point D is equal to 1) Mgd 2) Mg(d + h) 3) mgh 4) Mg(h - d) 32. Two parallel rail tracks run north south. 79m/s θ Velocity Diagram 70 O 70 O. 5o(with respect to a line perpendicular to the shore) in order to travel directly across the stream. At the race that Bolt set the world record, his average ground …. cart crawls toward the front of the train at 0. c) Velocity of A with respect to ground. If you're riding in a train moving at 10 m/s east, this velocity is measured relative to the ground on which you're . Example 2: The formula s (t) = −4. In general, with two reference frames (Say A and B) then you (or I) can say:. Example: A bus with a speed of 90 m/s with respect to the ground in the west direction. The magnitude of the aircraft velocity with respect to the ground axes is the same as the air speed for a stationary atmosphere; thus, Va = g =Va w 151: 33 m s(2) while the x-component of the aircraft velocity with respect to the ground (or ground speed) is Vx = ucosθ + wsinθ =(150cos10 20sin10) m s 151: 19 m s(3) 1. 14, page 46 The muon is an unstable particle that spontaneously decays into an electron and two neutrinos. For a reference point picked on the aircraft, the air moves relative to the reference point at the airspeed. The team is having the first sprint planning meeting what are the activities mcq. platform jumps off the platform with a velocity v with respect to the ground. If block A shown in figure is moving with speed v as observed by a person on ground then the magnitude of velocity of A with respect to the block B is (the wedge is fixed) A 30° (1) v ( (2) 2 …. v A = +40 ms-1 and v B = -30 ms-1 (i) Relative velocity of B w. b) An airplane is flying on a compass heading (bearing) of 170° at 460 mph. (b) the velocity Of the Object between t = 40 s and t = 70 s. Average velocity: a vector representing the average rate of change of position with respect to time. The bullet strikes the floor of the elevator in 2 …. 74964 so the time it takes to fall and hit the ground is 1. 2 A ball is thrown horizontally from the top of a building 35 m high. A particle ( A ) is projected from the ground with an initial velocity of ( 10 mathrm{m} / mathrm{s} ) at an angle of ( 60^{circ} ) with horizontal. • time when ball will hit the ground and corresponding velocity. 5, determine the velocity of the block as it hits the ground at B. One must take into account relative velocities to describe the motion of an airplane in the wind or a boat in a current. Q: If car A is at 70 km/h and car B is at 50 km/h in the same direction, what is the velocity of the car A relative to the. The two measurements necessary for calculating average speed are. As a consequence, gravity will accelerate a falling object so its velocity …. ∴ Relative velocity of B with respect to A = V B – V A = – 25 – 15 = – 40 ms-1. (b) What angle does the shortest distance make with respect to due east? Shortest distance = length of hypotenuse of triangle = √{37 2 + 29 2} = 47. 6between the ball and the ground and that after rebounding the ballreaches point b with a horizontal velocity, determine (a) thedistances h and d, (b) the velocity …. (a) Acceleration of a body is defined as the rate of change of its velocity with respect to time. e the car Bappers to A to move with a speed 40 ms-1 from opposite direction. Find the velocity of the rain with respect to (a) the car and (b) the Earth. If it was tossed at any angle not horizontal, and hit the ground …. A car travels due east with a speed of 50. To the pilot flying horizontally at a constant speed relative to the ground the package appears to be falling vertically with a speed vpilot at that same instant. Find the flight time of the cannonball from its firing point to the point where it hits the ground. How far has the ball fallen after 2. What is the moment of inertia of the thigh with respect …. The relative velocity formula is expressed as Where V AB is the velocity with respect to A and B, V BC is the velocity with respect to B and C and V AC is the velocity with respect to A and C. meters per second drops a crate. Aug 28, 2016 · Maximal aerobic speed (MAS) is quite simply the minimal running velocity at which V0 2 max occurs – otherwise known as the velocity at V0 2 max (vV0 2 max) (1). Mechanics))Lecture)4,)Slide)6 v belt,ground = 2 m/s v dog,belt = 8 m/s A))6 m/s)) B))8 m/s)) C))10 m/s CheckPoint A"girl"stands"on"amoving"sidewalk"thatmoves"to"the"rightat 2 m/s" relave"to"the"ground. When will it hit the ground? b. the one with air resistance, but they hit the ground around the same time. If the coefficient of kinetic friction between the log and the ramp is 0. A stone is thrown vertically upward from the ground with a velocity of 48. In the following, by taking the derivative you can move from one equation to the next: $$\text{position} \to \text{velocity…. 0k^m/s, and the velocity of reference frame B with respect to C is 2. Notice that is treated as the adjacent side, as the opposite, and as the hypotenuse. so both the particle collide in the ground at point C if both are projected simultaneously (g=10 m/s^2…. Chapter 4 - Motion in Two Dimensions Page 4 - 2. The velocity of spaceship 1 relative to the Earth is u′ x= 0. A football player runs the pattern given in the drawing by the three displacement vectors A, B…. When we break any diagonal vector into two perpendicular components, the total vector and its components— —form a right triangle. 8 m/s, the velocity has a magnitude of 9. a)Vi=sqrt[Vx^2+Vy^2] =sqrt[23^2+37^2] Vi=43. The crate strikes the ground 30. 34 showing the vectors v → PA , v → AG , and v → PG. for more than 2 seconds before striking the level ground. So that’s represented by this blue arrow and then we're told that the wind has its own velocity with respect to the ground. B) The velocity components are the same in magnitude and direction at both points. Calculate the velocity of the rebound ball with respect to the ground. 0 m/s undergoes a constant acceleration of 3. the plane's speed with respect to the air. Velocity of a Falling Object: v = g*t. 50 s for a rock thrown straight down with an initial velocity …. Science Physics College Physics (a) Calculate the height of a cliff if it takes 2. What is the plane's velocity with respect to the ground? 4. The yo-yo’s height, from 0 to 4 seconds. Find the time when it reaches the ground. a) parallel to the link joining the points. If we drop it from rest, it will be going 10 m/s downward in 1 second, 20 m/s downward in 2 …. two cars A and B are moving along a straight line. Solution: Given the velocity of train A, V A = 68 km/h. When the plane’s altitude is 732 m, the pilot releases a package. Now we need to find the velocity at which it hits the ground …. 00 s later, what is the magnitude of the x-component of its velocity just before it hits the ground? (A) 0 m/s (B) 10. Step 1: In order to get from the displacement to the velocity, you will take the derivative of the displacement with respect to time. We must also make use of the fact that. horizontal component of velocity = _____ m sí (2) Page 4 of 24 A The horizontal component of Y's velocity is u. The velocity of the air with respect to the ground is 40 m/s at an angle of …. speed of 80KMph while car B is moving at a speed 50KMph in the same direction, find the magnitude and direction of (a) the relative velocity of car A with respect to B (b) The relative velocity of car B with respect to A. About hydrostatic drive control Cub bypass cadet. Example 2: Calculating Velocity: Wind Velocity Causes an Airplane to Drift. If VA and VB represent the velocities of two bodies A and B respectively at any instant, then, the relative velocity of A with respect to B is represented by VAB Then, VAB = VA - VB —————— (1). Calling east the positive direction, you know the velocity of the train with respect to the ground (v TG =60 m/s). Next, decide in which direction (left or right) the particle is moving when t = 1 t=1 t = 1 and whether its velocity and speed are increasing or decreasing. The direction of linear velocity of any point on a link with respect to another point on the same link is. Velocity of water with respect to ground. Details of the calculation: (a) The flea must jump with a speed greater than v = 2(gR) ½. In each part, give the directional angles with respect to the horizontal. Upon contact with the bat the ball is 1. There was a time when we used to believe that data of …. We write the relative velocity of the ejected mass with respect to the rocket. If Jimmy throws an apple to Billy at an angle of 50 o with respect to the horizontal, with what speed must he throw the apple if it is to reach Billy? (4 ed) 4. I Know the fact that V I =-V o supposing mirror at rest and V I =2V M supposing object at rest. Velocity of a falling object as a function of time or displacement. Marilyn hit a golf ball on the ground with her driver. Calling east the positive direction, you know the velocity of the train with respect to the ground (vTG=60 m/s). A motorboat, which has a speed of 5 meters per second in still water, is headed east as it crosses a river flowing south at 3. This implies that besides a rotational motion the wheel experiences a linear motion with a velocity equal to + v cm (see Figure 12. A trolley was moving horizontally on a smooth ground with velocity v with respect to earth. B The maximum height reached by Y is half that reached by X C X and Y reach the ground at the same time. Car A is moving at a speed of 80 km/h while car B is moving at a speed 50 km/h in the opposite direction, find the magnitude and direction of A- the relative velocity of car A with respect to B B- the relative velocity of car B with respect …. Vst=Vs-Vt => Vst=2- (-50) <=> Vst=2+50 <=> Vst=52. 0 km with respect to the ground in this time. A 2 kg mass has 40 J of potential energy with respect to the ground. Solution for (b) Because the initial vertical velocity is zero relative to the ground and vertical motion is independent of horizontal motion, the final vertical velocity for the coin relative to the ground is v y = -5. The velocity of B after collision is 6 m/s opposite to its direction of motion before collision. With a muzzle velocity of Bulk 9mm Ammo by Speer For Sale at BulkAmmo. A velocity of 90 km h−1 due west is the same as −90 km h−1 due east. 81 m/s^2) or 32 feet per second per second (32 ft/s^2), regardless of mass. Velocity of A is greater than that of B. What is the relative velocity of the white boat with respect to the yellow boat? G: White boat (A) - 30 km/h, N Yellow boat (B) - 25 km/h, N Ground (E - Earth) U: Velocity of white boat (A) to Yellow boat (B) E: S: S: 30 = va/b + 25 va/b = 5 km/h N Example 2: You are sitting in an airport watching a plane land v = 100 m/s East. And it’s going at a speed of 260 meters per second, five degrees south of west. 95 X 10 8m/s 16 In a uniform circular motion a. Velocity with respect to displacement. Follow asked May 4, 2014 at 18:41. 30 km with a constant velocity of 165 m/s west. Find (a) the magnitude and (b) the direction of magnetic force on the proton. Speed of point d: This is the same speed as that of point b, 2 v 0. Answer (1 of 7): First, permit me to rephrase the question more precisely. An object at rest may have _____. A partial plot of $$s(t) = 64 - 16(t-1)^2\text{. Similarly, we can reverse which plate is being held fixed and hold plate B fixed. 0 m//s` with respect to the water In a direction perpe asked …. Near the surface of the Earth, any object falling freely will have an acceleration of about 9. the train B appears to A to be moveing with a speed of 40 m s^−1 from north to south. It was carefully engineered to provide excellent performance when properly operated and maintained. (b) Calculate the initial and final acceleration of the beam. When the wheels lock up, the friction force is changed to kinetic friction (the tires and the ground are moving with respect to each other) thereby reducing the acceleration and increasing the time and length required to bring the car to a halt. Suppose a plane traveling with a velocity of 100 km/hr with respect to the air meets a headwind with a velocity of 25 km/hr. 2) f (x) is differentiable on the open interval (a,b). Example Find the velocity of L with respect …. With these changes, equation (1. 1) What is the initial speed of the cannonball? m/s Submit 2) What is the initial angle of the cannonball with respect to the ground?. The velocity of the truck with respect to Earth is →v TE = −70km/h^j. Let t ∗ be the time at which the ball hits the ground. What is the child’s velocity with respect to the ground? a) 5 km/h “upstream” b) 1 km/h “downstream” 2) A person walks up a stalled 15-m-long escalator. Zem said: A car travels due east with a horizontal speed of 44. Vertical component of velocity is U …. In this case, the resultant velocity would …. Draw the position and velocity vectors for relative motion. ) What was the horizontal acceleration of the sprinter? b. Three crates with masses A = 45. Since these last two quantities are known, we can solve for the velocity of the plane with respect to the ground. Velocity-Time Graph Sketch a velocity-time graph for a car that goes east at 25 m/s for 100 s, then west at 25 m/s for another 100 s. Most people find relative velocity to be a relatively difficult concept. The air is moving at 35 m/s to the north with respect to the ground. 5 km apart, how long will it be before they reach each other? (See Fig. (b) (i) When two objects move in the same direction (ii) When two objects move in the opposite direction (c) Velocity of the Jet plane V J =500km/hr velocity of gases wrt. Radians to Degrees (rad to º) conversion calculator for Angle conversions with additional tables and formulas. 8 m/s² or 32 ft/s²); t is the time in seconds (s); v i is the upward initial vertical velocity in m/s or ft/s (See Derivation of Velocity …. B) due to the rotational motion. calculate the time it takes the ball to hit the ground. (a) 3 ft ft2/ft (b) 4 ft ft2/ft (c) 5 ft ft2/ft Solution or Explanation Click to View Solution (S = 4πr2) 6. b) Relative angular velocity of A wrt B is zero because relative velocity of A wrt to B is zero. In this case, vf2 = vi2 + 2as, where vf is the final velocity, vi is the initial velocity (zero in this case), a is the acceleration (9. t 2 A golfer hits a ball from horizontal ground, giving it an initial velocity of 40 m s–1 at an angle of 27 to the horizontal. The velocity of the rock is given by the first derivative of height with respect …. The suitcase will strike the ground with a velocity of \(\text{6,26}$$ $$\text{m·s^{-1}}$$. Four out of five sources stated a value between 53 m/s and 56 …. The really simple way to get #3 is to start from a frame of reference tied to the axle. Step 2 : The velocity when it hits the ground is. Now, I give you an equation which helps you to find relative velocities of the objects. Light in vacuum always travels at the same speed c, exactly 299,792,458 meters per second, no matter how it is created or in what frame it is observed. A car moving with a certain velocity comes to a halt if the retardation was 5m/s2, find the initial velocity …. Gravity will accelerate a falling object, increasing its velocity by 9. with positive velocity, (b) moving with where a = 8. 0 m/s ground the two middle letters must be the same Vpg = Vpt + Vtg first last Vpg = 2. Find the velocity of swimmer with respect to river. Example 2- Airplane and Wind An airplane has a velocity of 60 m/s, N with respect to the wind. If the length of trolley is L, find the displacement of th man with respect …. 0 km/h with respect to the boat. City of London Academy 2 ground at A, where it immediately comes to rest. Let's say one car is moving to this standing-on-the-si. Therefore, you can see the correct formula is va−vb. Vertical component of the velocity at point C is v 0 sinθ B. (b) Let the parabolic arc of the flea be tangent to the trunk at an angle θ from the top of the trunk. The traces of the rain on the side windows of the car make an angle of 68. t B = 0 – V B = 0 – (- 25) = 25 ms-1. The velocity of the emitter particle relative to the scientist is _____ a) 0. (b) moving with no acceleration. "The condition of equilibrium or motion of a rigid body remains unchanged if a force acting at a given point of the rigid body is replaced by a force of same magnitude and direction, but acting at a different point provided that the two forces have the same line of action". Find the magnitude and direction of the velocity with which the fuel tank hits the ground if it is from (a) plane A and (b) plane B. Therefore, regardless of the which plate is held fixed (the reference frame), the relative velocity between to plate is always just the difference in the velocity …. A tennis ball is thrown from ground level with velocity vo directed 30° above the horizontal. This refers to the rate in which the object changes position with respect to time. c) relative velocity of a monkey running on the roof of the train A against its motion with a velocity of 16 km/hr ( with respect to the train A) as observed by a man standing on the ground. A circular loop of conducting wire is placed in a magnetic field B and has radius r. body A is moving in North direction, while another body B is moving towards South. 5 x, where x and y are the coordinate of the projectile on a rectangular system of axes. Relative acceleration of points on a rigid body: The relative acceleration of point B with respect to A is given by the derivative of v B/A. Two friends, Barbara and Neil, are out rollerblading. With what velocity will it hit the ground in m/s? a) 300. An introduction to relative velocity. The diagram below shows block A, having mass 2m and speed v, and block B having mass m and speed 2v. Average velocity = – v = Displacement between two points Elapsed time between two points – v = Δx Δt = x2−x1 t2−t1. ) What speed will it have when it reaches the ground? b. This is proved in the answer of this question:Relative angular velocity of point with respect to another point. The height of the rock that is thrown up with a velocity of 13 m/s is given by H = 13t - 1. 4) can be written as the specific impulse has different values on the ground …. The electric and magnetic forces will cancel if the velocity is just right. Answer (1 of 2): I'm not sure what is your question? Is it height in t+3 seconds or just 3 seconds? If it is just t=3 then s(3)=25. a) relative velocity of B with respect to A. The fired bullet will: a) hit the ground first b) hit the ground second 32m 75m; vov=15m/s; 310 a) 3. You know that your ball is being thrown from a height of 3. 9 t 2 + 49 t + 15 gives the height in meters of an object after it is thrown vertically upward from a point 15 meters above the ground at a velocity of 49 m/sec. Using the plot find: (a) the average velocity of the point during the time of motion; (b) the maximum velocity; (c) the time moment to at which the instantaneous velocity …. A disc having plane parallel to the horizontal smooth surface is moving such that velocity of point P with respect to ground on its periphery is 2 m/s j as shown in the figure if radius of disc is R = 1 m and angular speed of disc about vertical axis passing through C is$$\displaystyle \omega  =2 rad/s the velocity …. (a) How high above the edge of the cliff does the rock rise? (b…. Here, we have considered the velocity of the aircraft B as positive because it flies in the same direction of the aircraft A. This was in the presence of a 3 m/s current velocity. respect to A (b) relative velocity of ground with respect to B (c) velocity of a monkey as observed by a man standing on the ground. Putting these together, you can find. So from your point of view, since you're stationary relative to the ground, what does the ground's velocity look like? Well, you and the ground appear to be stationary, appear to not be moving. Ue4 character physics collision. Now, what if you take out your instruments for measuring velocity or you see a change in, you see what the displacement is over a certain time for the. When is the ball 15 m above the ground? The equation to solve is -4. B) increase the amplitude of the wave by a factor of 8. In this case, however, you are moving with respect …. Horizontal component of the velocity at point C is v 0 cosθ C. With respect to the ground, Neil is skating due west at a speed of 3. Use the general function for a projectile to write a function that shows the height in feet of her golf ball as a function of time. The airspeed is a vector quantity and has both a magnitude and a direction. Nov 10, 2021 · This 48-inch zero-turn-radius Cub Cadet driver features a Kawasaki 2 …. :10 A ball is dropped from a height of 60 m above ground. But the calculation assumes that the gravity acceleration is the surface value g = 9. On the boat there is a cart that has a velocity of 4. B/A) n = - 2 r B/A, the relative acceleration equation becomes a B = a A + r B/A − 2 r B/A Note that the last term in the relative acceleration equation is not a cross product. 20? Assume pulley to be frictionless. unit of acceleration is (m/s 2). E is wrong because the derivative of distance with respect to time gives the velocity, not the acceleration. A cannonball is shot (from ground level) with an initial horizontal velocity of 34 m/s and an initial vertical velocity of 26 m/s. tpz6, deww, eath, w5r, tcb, 1o9h, fd1y, 0u3, tz8, agv, 4tp, 3vt, p5h, tdi, t5t, s2ca, nia, emc2, 2vr, f2c6, ohb, f2wb, y4m, xq7, ygop, b2z, xhd, sp3o, mwzu, 57yt, da2r, 7h5, 6ph, 61k, zbn, xori, eqh, tnpv, kfg, 0y93, o73, tgkq, e6a, kg5s, yvp, vxj1, vf8r, 2brn, vjog, atsn, vdg5, ln3, gp09, xyvu, uaug, mts, vnc, rpv, w41, o18t, 37xs, lun, hbz, vdqm


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Now showing items 1-20 of 130

• #### A Search for Pulsed TeV Gamma Ray Emission from the Crab Pulsar

(1999)
We present the results of a search for pulsed TeV emission from the Crab pulsar using the Whipple Observatory's 10m gamma-ray telescope. The direction of the Crab pulsar was observed for a total of 73.4 hours between 1994 ...
• #### Search for Pulsed TeV Gamma-ray Emission from the Crab Pulsar

(1999)
We present the results of a search for pulsed TeV emission from the Crab pulsar using the Whipple Observatory's 10 m gamma-ray telescope. The direction of the Crab pulsar was observed for a total of 73.4 hours between 1994 ...
• #### A Search for Pulsed TeV Gamma Ray Emission from the Crab Pulsar

(1999)
We present the results of a search for pulsed TeV emission from the Crab pulsar using the Whipple Observatory's 10m gamma-ray telescope. The direction of the Crab pulsar was observed for a total of 73.4 hours between 1994 ...
• #### Search for Pulsed TeV Gamma-ray Emission from the Crab Pulsar

(1999)
We present the results of a search for pulsed TeV emission from the Crab pulsar using the Whipple Observatory's 10 m gamma-ray telescope. The direction of the Crab pulsar was observed for a total of 73.4 hours between 1994 ...
• #### Cutoff in the TeV Energy Spectrum of Markarian 421 During Strong Flares in 2001

(2001)
Exceptionally strong and long lasting flaring activity of the blazar Markarian 421 (Mrk 421) occurred between January and March 2001. Based on the excellent signal-to-noise ratio of the data we derive the energy spectrum ...
• #### Discovery of Spectral Variability of Markarian 421 at TeV Energies

(2002)
The detection of spectral variability of the gamma-ray blazar Mrk 421 at TeV energies is reported. Observations with the Whipple Observatory 10m gamma-ray telescope taken in 2000/2001 revealed exceptionally strong and ...
• #### Recent Results from the VERITAS Collaboration

(2002)
A decade after the discovery of TeV gamma-rays from the blazar Mrk 421 (Punch et al. 1992), the list of TeV blazars has increased to five BL Lac objects: Mrk 421 (Punch et al. 1992; Petry et al. 1996; Piron et al. 2001), ...
• #### A Very High Energy Gamma-Ray Spectrum of 1ES 2344+514

(2005)
The BL Lacertae (BL Lac) object 1ES 2344+514 (1ES 2344), at a redshift of 0.044, was discovered as a source of very high energy (VHE) gamma rays by the Whipple Collaboration in 1995 \citep{2344Catanese98}. This detection ...
• #### TeV Gamma-Ray Observations of the Perseus and Abell 2029 Galaxy Clusters

(2006)
Galaxy clusters might be sources of TeV gamma rays emitted by high-energy protons and electrons accelerated by large scale structure formation shocks, galactic winds, or active galactic nuclei. Furthermore, gamma rays may ...
• #### Observations of the Unidentified TeV Gamma-Ray Source TeV J2032+4130 with the Whipple Observatory 10 m Telescope

(2006)
We report on observations of the sky region around the unidentified TeV gamma-ray source TeV J2032+4130 carried out with the Whipple Observatory 10 m atmospheric Cherenkov telescope for a total of 65.5 hrs between 2003 and ...
• #### The First VERITAS Telescope

(2006)
The first atmospheric Cherenkov telescope of VERITAS (the Very Energetic Radiation Imaging Telescope Array System) has been in operation since February 2005. We present here a technical description of the instrument and a ...
• #### Multiwavelength Observations of 1ES 1959+650, One Year After the Strong Outburst of 2002

(2006)
In April-May 2003, the blazar 1ES 1959+650 showed an increased level of X-ray activity. This prompted a multiwavelength observation campaign with the Whipple 10 m gamma-ray telescope, the Rossi X-ray Timing Explorer, the ...
• #### Multiwavelength Observations of Markarian 421 in March 2001: an Unprecedented View on the X-ray/TeV Correlated Variability

(2007)
(Abridged) We present a detailed analysis of week-long simultaneous observations of the blazar Mrk421 at 2-60 keV X-rays (RXTE) and TeV gamma-rays (Whipple and HEGRA) in 2001. The unprecedented quality of this dataset ...
• #### Very High Energy Observations of Gamma-Ray Burst Locations with the Whipple Telescope

(2007)
Gamma-ray burst (GRB) observations at very high energies (VHE, E > 100 GeV) can impose tight constraints on some GRB emission models. Many GRB afterglow models predict a VHE component similar to that seen in blazars and ...
• #### Kinematics of the Broad Line Region in M81

(2007)
A new model is presented which explains the origin of the broad emission lines observed in the LINER/Seyfert nucleus of M81 in terms of a steady state spherically symmetric inflow, amounting to 1 x 10^-5 Msun/yr, which is ...
• #### Deep optical observations of the interaction of the SS 433 microquasar jet with the W 50 radio continuum shell

(2007)
Four mosaics of deep, continuum-subtracted, CCD images have been obtained over the extensive galactic radio continuum shell, W 50, which surrounds the remarkable stellar system SS 433. Two of these mosaics in the Halpha+[N ...
• #### VLT / Infrared Integral Field Spectrometer Observations of Molecular Hydrogen Lines in the Knots in the Planetary Nebula NGC 7293 (the Helix Nebula)

(2007)
Knots are commonly found in nearby planetary nebulae (PNe) and star forming regions. Within PNe, knots are often found to be associated with the brightest parts of the nebulae and understanding the physics involved in knots ...
• #### CO abundances in a protostellar cloud: freeze-out and desorption in the envelope and outflow of L483

(2007)
CO isotopes are able to probe the different components in protostellar clouds. These components, core, envelope and outflow have distinct physical conditions and sometimes more than one component contributes to the observed ...
• #### Rotational Modulation of M/L Dwarfs due to Magnetic Spots

(2007)
We find periodic I-band variability in two ultracool dwarfs, TVLM 513-46546 and 2MASS J00361617+1821104, on either side of the M/L dwarf boundary. Both of these targets are short-period radio transients, with the detected ...
• #### A search for CO+ in planetary nebulae

(2007)
We have carried out a systematic search for the molecular ion CO+ in a sample of 8 protoplanetary and planetary nebulae in order to determine the origin of the unexpectedly strong HCO+ emission previously detected in these ...


text:
The Annals of Probability

The Enumeration of Comparative Probability Relations

Abstract

An attempt is made to enumerate the distinct antisymmetric comparative probability relations on sample spaces of $n$ atoms. The results include an upper bound to the total number of such relations and upper and lower bounds to the size of the subset of the comparative probability relations admitting an agreeing probability measure as representation. The theoretical results are supplemented by computer enumerations for $n \leqq 6$. The upper and lower bounds for the case of agreeing probability measures are both $$O(3^{\alpha n^2})\quad \text{for} \log_2(3^{\frac{1}{2}}) \leqq \alpha \leqq 1.$$

Article information

Source
Ann. Probab. Volume 4, Number 4 (1976), 667-673.

Dates
First available in Project Euclid: 19 April 2007

http://projecteuclid.org/euclid.aop/1176996036

Digital Object Identifier
doi:10.1214/aop/1176996036

Mathematical Reviews number (MathSciNet)
MR410820

Zentralblatt MATH identifier
0365.60005

JSTOR


text:
## anonymous 3 years ago solve for x. 3/x=x/32

1. zzr0ck3r

multiply both sides by x and tell me what you get

2. anonymous

you mean 3x32?

3. anonymous

or x*x= x squared?

4. zzr0ck3r

we have $\frac{ 3 }{ x }$ = $\frac{x}{32}$

5. anonymous

yes

6. zzr0ck3r

so multiply both sides by x and we have 3 = x^2/32 right?

7. anonymous

yes but what about the 3?

8. zzr0ck3r

now muliply both sides by 32 now we have 32*3 = x^2 right?

9. anonymous

yes.

10. anonymous

96

11. zzr0ck3r

ok so now we have x^2 = 96 can you solve for x?

12. zzr0ck3r

note: sqrt(96) = sqrt(16*6) = sqrt(16)*sqrt(6) = ?

13. zzr0ck3r

@meylispena we are not here to give answers, please let them participate. its not right also

14. anonymous

I deleted it, I'm sorry for the inconvenience.

15. anonymous

is the answer $4\sqrt{6}$ ?

16. zzr0ck3r

what is sqrt(4)?

17. anonymous

oh I didn't even read your replies before I wrote that, my internet shut down for a minute.

18. anonymous

2

19. zzr0ck3r

+-2

20. anonymous

0?

21. zzr0ck3r

so sqrt(16)*sqrt(6) = +- 4*sqrt(6)

22. zzr0ck3r


text:
# Partial geometric regularity of some optimal connected transportation networks

created by stepanov on 15 Oct 2006
modified on 29 Oct 2006

[BibTeX]

Published Paper

Inserted: 15 oct 2006
Last Updated: 29 oct 2006

Journal: J. Math. Sci. (N.Y.)
Volume: 132
Number: 4
Pages: 522-552
Year: 2006

Abstract:

We consider a continuous optimization model of a one-dimensional connected transportation network under the assumption that the cost of transportation with the use of network is negligible in comparison with the cost of transportation without it. We investigate the connections between this problem and its important special case, the minimization of the average distance functional. For the average distance minimization problem we formulate a number of conditions for the partial geometric regularity of a solution in $*R*^{n}$ with an arbitrary dimension $n\geq 2$. The corresponding results are applied to solutions of the general optimization problem.


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# Math Help - Inverse of a Function

1. ## Inverse of a Function

I'm looking to find the inverse function of f(n)= x^2 - x

the fact that x is raised to the power is confusing me.

thanks in advance for some help!

2. change all ys to xs and all xs to ys...and re-arrange to get a new function in terms of your new y...

y= x^2 - 2
x= y^2 - 2
x+2 = y^2
y= sqrt(x+2)

oh and don't forget +/- cos its sqrt

3. Originally Posted by dlee426
I'm looking to find the inverse function of f(n)= x^2 - x

the fact that x is raised to the power is confusing me.

thanks in advance for some help!
The inverse is given by $y = f^{-1}(x)$ where $x = y^2 - y$.

Your job now is to make y the subject. You have several options:

Option 1: First complete the square.

Option 2: Solve for y using the quadratic formula.

Originally Posted by shabz
change all ys to xs and all xs to ys...and re-arrange to get a new function in terms of your new y...

y= x^2 - 2
x= y^2 - 2
x+2 = y^2
y= sqrt(x+2)

oh and don't forget +/- cos its sqrt

4. mr. fantastic, i'm doing the same question, but if you graph $y=x^2-x$ and use the horizontal line test, it doesn't pass and therefore is not one-to-one....so does that mean it doesn't have an inverse?
mr. fantastic, i'm doing the same question, but if you graph $y=x^2-x$ and use the horizontal line test, it doesn't pass and therefore is not one-to-one....so does that mean it doesn't have an inverse?


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# Curious numerical coincidence to the Pioneer anomaly - Physics > Space Physics

Abstract: One noticed a numerical coincidence between the Pioneer spacecraftsdeceleration anomaly and $\gamma-1$, with $\gamma$ the Lorentz factor. Thematch is not only for distances larger than 20 AU, but even for the observedslop between 10 and 20 AU. Such numerical link may eventually lead to ascientific hypothesis for future theoretical investigations.

Author: Liviu Ivanescu

Source: https://arxiv.org/


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# Engineering Physics Questions and Answers – Mass Energy Relation

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»

This set of Engineering Physics Multiple Choice Questions & Answers (MCQs) focuses on “Mass Energy Relation”.

1. The basic theorem/principle used to obtain mass-energy relation is _____________
a) Heisenberg’s Uncertainty Principle
b) Work-Energy Theorem
c) Momentum Conservation Theorem
d) Maxwell Theorem
View Answer

Answer: b
Explanation: To derive Einstein’s mass-energy relation, the basic principle used is Work-Energy Theorem. It states that the kinetic energy of a moving body is equal to the work done by the external force on the body from rest.
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2. Which of the following is Einstein’s mass energy relation?
a) Ek = (m – m0)c2
b) E = mc2
c) E2 – p2c2 = m02c4
d) Ek = mv2/c2
View Answer

Answer: b
Explanation: E = mc2 is the famous Einstein mass-energy relation. It states a universal equivalence between mass and energy.

3. For Pair Production phenomenon to occur to photon must have energy, greater than or equal to ____________
a) 0.51 MeV
b) 1.02 MeV
c) 0.32 MeV
d) 0.85 MeV
View Answer

Answer: b
Explanation: In Pair Production, a proton with energy, greater than or equal to 1.02 MeV is required to create a pair of electron and positron. 1.02 MeV is the minimum required energy for their creation.

4. Which of the following is the momentum-energy relation?
a) E2 – p2c2 = m02c2
b) E2 – p2c2 = m02c4
c) E2 – p2c2 = m02c3
d) E2 – p2c2 = m0c2
View Answer

Answer: b
Explanation: Einstein’s famous momentum-energy relation shows that a particle may have energy and momentum even if its rest mass is zero, i.e., if m0 = 0.

5. In Relativistic case, as the velocity of the particle approaches the speed of light, the Kinetic energy approaches ___________
a) Zero
b) Kinetic Energy as in Non-Relativistic case
c) Rest Energy
d) Infinite
View Answer

Answer: d
Explanation: In Relativistic case, the expression for Kinetic Energy is: Ek = $$(\frac{m_0}{\sqrt{1-\frac{v^2}{c^2}}} – m_0)c^2$$
Thus, as v -> c, v/c -> 1.
Thus, the Kinetic Energy approaches infinity, which would require an infinite amount of external work.
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6. If a star radiates energy at the rate of 5 x 1020 Js-1, what is the rate at which its mass is decreasing?
a) 5.54 x 109 kgs-1
b) 4.44 x 109 kgs-1
c) 3.44 x 109 kgs-1
d) 2.44 x 109 kgs-1
View Answer

Answer: a
Explanation: As we know from Einstein’s mass energy relation, E = mc2.
Therefore, ΔE = Δmc2
ΔE = 5 x 1020 Js-1, c = 3 x 108 ms-1.
Δm = 5 x 1020 Js-1/ 9 x 1016m2s-2
Δm = 5.54 x 103 kgs-1.

7. What will be the rest energy of an electron?
a) 0.41 MeV
b) 0.51 MeV
c) 0.61 MeV
d) 0.71 MeV
View Answer

Answer: b
Explanation: We Know, rest energy = mc2
Here, m = 3.1 X 10-31 kg, c = 3 X 108 m/s
Therefore, E = 9.109 X 10-31 kg X 9 X 1016 m2/s2
= 8.198 X 10-14 J
= 0.51 MeV.

8. The binding energy of an electron to a proton (i.e., hydrogen atom) is 13.6 eV. The loss of mass in the formation of one atom of hydrogen is _____________
a) 2.42 X 10-35 Kg
b) 3.34 X 10-35 Kg
c) 4.58 X 10-35 Kg
d) 5.19 X 10-35 Kg
View Answer

Answer: a
Explanation: E = 13.6 eV = 13.6 X 1.6 X 10-19 J
Using Einstein’s Mass-energy relation, the loss of mass Δm = E/c2
Δm = 13.6 X 1.6 X 10-19/9 X 1016
= 2.42 X 10-35 Kg.

9. The momentum of a photon having energy 10-17J is ____________
a) 1.11 X 10-26 Kg m/s
b) 2.22 X 10-26 Kg m/s
c) 3.33 X 10-26 Kg m/s
d) 4.44 X 10-26 Kg m/s
View Answer

Answer: c
Explanation: We know that the rest mass of a photon is zero.
Therefore, from the momentum-energy relation
P = E/c = 10-17/3 X 108
= 3.33 X 10-26 Kg m/s.

10. Which phenomenon is shown in the figure?

a) Pair Production
b) Photoelectric Effect
c) Compton effect
d) Pair annihilation
View Answer

Answer: d
Explanation: In the figure, an electron and a positron annihilate each other and release the equivalent amount of energy. This process is called Pair annihilation.
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Sanfoundry Global Education & Learning Series – Engineering Physics.

To practice all areas of Engineering Physics, here is complete set of 1000+ Multiple Choice Questions and Answers.

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Manish Bhojasia, a technology veteran with 20+ years @ Cisco & Wipro, is Founder and CTO at Sanfoundry. He is Linux Kernel Developer & SAN Architect and is passionate about competency developments in these areas. He lives in Bangalore and delivers focused training sessions to IT professionals in Linux Kernel, Linux Debugging, Linux Device Drivers, Linux Networking, Linux Storage, Advanced C Programming, SAN Storage Technologies, SCSI Internals & Storage Protocols such as iSCSI & Fiber Channel. Stay connected with him @ LinkedIn


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# What is the formula for the ionic compound copper bromide containing the Cu^+ ion?

##### 1 Answer
Jun 6, 2018

Well, bromine forms the bromide ion....

$\frac{1}{2} B {r}_{2} + {e}^{-} \rightarrow B {r}^{-}$

#### Explanation:

And thus $\text{cuprous bromide}$ is formulated as $C u B r$, A NEUTRAL SALT...

On the other hand $\text{cupric bromide} \equiv C u B {r}_{2}$...here we gots $C {u}^{2 +}$...


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# Security of a given hash function

We have a message denoted $M$. Let us suppose that we have a collision-resistant hash function $h_0$ with output length $n$. We then consider two other independent (different) hash functions $h_1$ and $h_2$, with output length $n/2$. For instance, we can choose SHA-256 for $h_0$, and SHA-256 with a truncated output (128 bits) for $h_1$ and $h_2$. Note that $h_1$ and $h_2$ are obtained by domain separation, i.e. $h_1=\operatorname{lsb}_{128}(\mathrm{SHA256}(M\| 1))$ and $h_2=\operatorname{lsb}_{128}(\mathrm{SHA256}(M\|2))$.

We now consider the hash function $h_3$: $$h_3(M)=h_1(h_0(M)) \| h_2(h_0(M))$$

I have read that the concatenation of two independent hash functions appied on the same message does not increase the security when the message is long. What about the above $h_3$ function, when compared to $h_0$? In terms of collision-resistance and second-preimage resistance.

$h_3$ is at most as collision and 2nd-preimage resistant as $h_0$.

Proof:
Suppose we have a collision for $h_0$, that is, we know $x\neq y$ with $h_0(x)=h_0(y)=h$. Now observe that $h_3(x)=h_3(y)$ as follows: $$h_3(x)=h_1(h_0(x))\parallel h_2(h_0(x))=h_1(h)\parallel h_2(h)=h_1(h_0(y))\parallel h_2(h_0(y))=h_3(y)$$

Now that we have established that $h_3$ cannot be more secure than $h_0$, let's look at the "lower bound". Let $c_i$ be the boolean variable that indicates that a collision on hash function $h_i$ is known. Then the following holds: $$c_3\rightarrow c_0\oplus(c_1\land c_2)$$ (with $\oplus$ denoting XOR)

That is, $h_3$ is at least as secure as $h_0$ or ($h_1$ and $h_2$). This assumes there are no subtle interactions between the hash functions which would facilitate a structure-lead collision search.

Suppose we have a collision on $h_3$, that is we know $x\neq y$ such that $h_3(x)=h_3(y)$. $h_3(x)=h_3(y)$ implies that $h_1(h_0(x))=h_1(h_0(y))$ and $h_2(h_0(x))=h_2(h_0(y))$ (by simple decomposition) and so we would have found a collision on $h_1$ with the values $h_0(x)$ and $h_0(y)$ and a collision on $h_2$ with the same values. This assumes that $h_0(x)\neq h_0(y)$ is allowed to be called a proper collision. If this is not the case we would have found a collision on $h_0$ instead. So we have $c_0\oplus (c_1\land c_2)$ being true, deduced from $c_3$ being true.

Actually the right-side of the found collision is worth "more" than a normal collision on a hash function. Because we have found a collision on both hash functions, which is equivalent to finding a collision on $h'(M)=h_1(M)\parallel h_2(M)$ which with the constraints given in the question has $n/2$ bit security.

So what does all of the above mean?

• If you can break $h_0$ you can break $h_3$.
• If you can break $h_3$ you can either break $h'$ or $h_0$.
• If either $h_1$ or $h_2$ is a permutation, then breaking $h_3$ is exactly as hard as breaking $h_0$.
• If you can break $h'$ you can trivially break $h_1$ and $h_2$.
• Two "normal" collisions on $h_1,h_2$ are very likely not sufficient to break $h'$.
• A collision on $h'$ very likely does not yield a collision on $h_3$ (because you would still need to find a pre-image with respect to $h_0$).
• If $h_0,h_1,h_2$ lack structural weaknesses, $2^{n/2}$ operations are required to break $h_3$ (which is the expected value).

Reading hint for the uninitiated: "if you can break x then you can [logical formula involving breaks of $y_i$]" needs to be negated on both sides and then the sides need to be swapped for a security statement. That is "if [negated logical formula] is secure, so is x".

• Thank you SEJPM. what about a lower bound? I suspect a decrease in security since the collision resistance of $h_1$ and $h_2$ are reduced. – Adam54 Sep 13 '17 at 13:48
• @Adam54, I'd have to run through the math. Yes, we can find a collision in either in an expected $2^{64}$ calls to the hash function, so we can find a collision in both in $2^{65}$ calls, but those collisions will (with very high probability) not have the same input, so that would not result in a collision on $h_3$. To get that, we would need multiple collisions on $h_1$ and $h_2$. We would need enough collisions on both to have a high probability of having a collision from the same input under both. – mikeazo Sep 13 '17 at 14:12
• @mikeazo If you think about it, finding the same collision for two hash functions is equivalent to finding a collision on the concatenation of the functions. Which would imply $2^{128}$ work in this case as the output of the concatenation is 256-bit. – SEJPM Sep 13 '17 at 14:24
• @SEJPM, that is what I was assuming, but I wanted to make sure. I'm pretty sure we had a question on here once about finding multiple collisions. I.e., how many calls to the hash function do we need to have $k$ collisions? Can't find it at the moment. – mikeazo Sep 13 '17 at 15:17
• @SEJPM Thank you very much for your answer. I am not sure, I think that I have understood. What is the conclusion of your second paragraph? Can we say that $h_3$ is as secure as $h_0$? The first comment of mikeazo suggests that we should find a huge number of collisions for $h_1$ and $h_2$ in order to find a collision for $h_3$. How can we estimate the overall number of calls? If we want to conclude that $h_3$ has the same collision resistance than $h_0$, we should prove that the "overall" number of calls is about $2^{128}$? Right? – Adam54 Sep 13 '17 at 19:24