Marginal benefit AP free response question

WEBVTT
Kind: captions
Language: en

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- [Instructor] We're told Martha
has a fixed budget of $20,

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and she spends it all on two
goods, good X and good Y.

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The price of X is $4 per unit,

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and the price of Y is $2 per unit.

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The table below shows the total benefit,

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measured in dollars, Martha receives

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from the consumption of each good.

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All right, we see that
here, this is total benefit,

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not marginal benefit.

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What is Martha's marginal benefit

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of the fifth unit of good X?

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So just to answer this
question, let's see,

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she has a total benefit of
$40 when she has four of X.

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And then when she goes to the fifth,

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her total benefit is an incremental $1.

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So she goes from $40 to $41.

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The marginal benefit of that
fifth one is that extra dollar.

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So we added a dollar of total benefit,

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so that's the marginal benefit.

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So it is $1.

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Calculate the total consumer surplus

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if Martha consumes five units of X.

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Show your work.

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Well, the consumer surplus
is going to be the benefit,

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benefit

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minus the cost, which
is going to be equal to,

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well, when she has five units of X,

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her total benefit is $41.

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So I'll write that here, $41.

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And then what's her
cost of five units of X?

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Well, X costs $4 per unit.

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So five times four is $20, so
her cost is going to be $20.

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So her consumer surplus

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is going to be equal to $21.

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Martha is currently
consuming four units of X

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and two units of Y.

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Use marginal analysis to explain

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why this combination is
not optimal for Martha.

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So pause this video, and
see if you can answer that.

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All right, well, let's just think about

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what the marginal benefit is

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from every incremental unit of X or Y,

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and then let's think about the
marginal benefit per dollar.

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So I'm gonna make an extra column here.

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Let's call this marginal benefit of X,

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and then let's call this
marginal benefit of Y.

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I'm doing it over this table
just for the sake of space.

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And so the marginal benefit

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of this first one is going to be 16.

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We went from zero to 16.

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The second one, we go from
16 to 28, so it's $12.

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And then to go from 28 to 36 is eight.

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To go from 36 to 40 is four
extra dollars of benefit.

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And to go from 40 to 41, we
already talked about that,

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that's $1 of marginal benefit.

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If we talk about Y, well, the first unit,

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you get $10 of benefit.

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The next one is the total
benefit increase eight, by $8,

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so that's the marginal
benefit of the next unit.

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The next one, to go from 18 to 24, six,

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to go from 24 to 28 is four more,

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and then 28 to 30 is two more.

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And then we could use this
information to think about

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marginal benefit of X

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per price of X,

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and we could also think
about marginal benefit of Y

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per price of Y.

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And so, let's see,

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and we're gonna start
with the first units.

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And so for this first unit,

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if you take the marginal benefit of X

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divided by the cost of a unit of X,

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$16 divided by $4 is going to get four.

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12 divided by four is three.

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Eight divided four is two.

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Four divided by four is one.

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And one divided by four is 0.25.

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And then for Y, the cost
of Y is $2 per unit.

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So the marginal benefit per dollar

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of this first unit right over
here is $10 divided by $2,

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which is five.

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Eight divided by two is four.

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Six divided by two is three.

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Four divided two is two.

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And then two divided by two is one.

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And so let's just think about

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what would be an optimal
combination for Martha.

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When she's thinking about
spending her first few dollars,

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she'll get a higher
marginal benefit per dollar

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by going with Y, so she's
going to start here.

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And then after that, her
second unit of Y has the same

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marginal benefit per dollar
as her first unit of X.

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So she's indifferent.

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She would do these in some order.

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So maybe she could do this one

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and then move on to that one,

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or, though, it could
go in the other order.

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And so far, she's only spent,

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let's see, $2, $2 is $4 plus another $4,

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she's only spent $8, and
she has a budget of 20.

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And then after that, her next incremental

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unit of either X or Y,

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the marginal benefit
per dollar is the same.

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So just thinking about whether this

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could be an optimal combination,

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she's already bought two units of Y.

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Let's just give the
benefit of the doubt here.

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Let's say that she goes for the X,

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so she buys this one here.

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But once she has two units of both,

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and she hasn't spent all of her money,

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she spent $8 here plus another $4.

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She has $8 to spend.

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The next rational thing for her to do,

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her marginal benefit per dollar
for that third incremental Y

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is higher than the third incremental X.

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So it would be optimal
for her to buy a third Y.

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But here, we see that she
only has two units of Y,

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so that's why we know it's
not an optimal combination.

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So we could say once

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she has

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two of each,

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the

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marginal benefit of Y

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per price of Y

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is greater than the marginal benefit of X

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per price of X for

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the third unit,

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so she will buy

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more than two Ys,

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let me write, let me scroll
down a little bit, buy more than

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two Ys.

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All right, the next they say is

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what is Martha's optimal
combination of goods of X and Y?

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Well, we've already started
that conversation up here.

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She would buy this Y, and
so far she spent $8 plus $6,

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so she has another $6 to spend.

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And then now her next incremental
unit, she's indifferent,

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so maybe she buys another Y.

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$8 plus $8, this is
$16, so she has $4 left.

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And so then she would buy this,

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and she has spent all of her
money, $12 here, $8 here.

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So she would buy three Xs and four Ys.

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So I would say three Xs

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and four Ys.

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All right part e, indicate
whether each of the following

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will cause the optimal quantity of good Y

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to increase, decrease, or stay the same.

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So look at these and pause this video,

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and see if you can answer those.

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So the price of good Y doubles.

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Well, if the price of good Y doubles,

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then the marginal benefit
per price of Y will go down.

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So she will buy less of
Y, so it would decrease.

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She would get less bang for her buck on Y,

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so she would buy less of Y.

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Martha's income falls to
$10 with no price changes.

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Well, if we go through
the exercise we just did,

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her budget would run out much faster,

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and so she would definitely decrease

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the number of Ys she would buy.

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So the Ys would decrease.

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Martha's income doubles, and
the price of both goods double.

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Well, in that case, things
would stay the same,

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stay the same.

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Because once again,

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she could buy that exact same combination.

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It would just cost twice as much,

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but then her budget is now twice as much.

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So things would stay the same.

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She would buy the same
quantities of both Xs and Ys,

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and they're just asking about Ys.

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And we're done.


Marginal utllity free response example

WEBVTT
Kind: captions
Language: en

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- [Instructor] We are
told that Theresa consumes

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both bagels and toy cars and they tell us

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that the table above shows
Theresa's marginal utility

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from bagels and toy cars.

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And the first question is,
what is her total utility

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from purchasing three toy cars?

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So pause this video and
see if you can answer that.

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All right now lets work
through this together.

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So let's just make sure we
understand this table here.

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So this says that the first
bagel that Theresa consumes,

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she gets eight units of
marginal utility from that.

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Then the second bagel,

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she gets a little bit
less marginal utility.

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Some or her bagel craving
has already been satisfied

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by that first one.

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And then the third bagel,
the marginal utility

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goes down a little bit and
then that keeps happening

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for each incremental bagel.

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And on the toy side, we
see that that first toy,

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she gets a lotta marginal utility, 10,

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and then the next toy
gets a little bit less,

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and then you see that the
marginal utility for each

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incremental toy gets a
little bit lower and lower.

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So now let's answer the first question.

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What is her total utility from
purchasing three toy cars?

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Well that first toy car,
she gets utility of 10.

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Then that second toy car,
she gets a utility of eight.

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And then that third toy
car, her marginal utility

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for that incremental car is six.

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So the total utility is going
to be 10 plus eight plus six,

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which is what, 10 plus 14,
this is going to be equal

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to 24 units of marginal utility.

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All right now let's do part two.

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Theresa's weekly income is $11,

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the price of a bagel is $2,

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and the price of a toy car is $1.

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What quantity of bagels
and toy cars will maximize

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Theresa's utility if she
spends her entire weekly income

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on bagels and toy cars?

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Explain your answer
using marginal analysis.

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So once again, pause
this video and see if you

00:02:00.280 --> 00:02:01.280
can figure that out.

00:02:02.120 --> 00:02:03.880
All right now let's do this together.

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I'll scroll down a little
bit so I have some space.

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So the key thing is, is
when once we know the price

00:02:10.110 --> 00:02:12.780
of a bagel and the price
of a toy and we know

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the marginal utility for every
incremental bagel or toy,

00:02:15.630 --> 00:02:17.680
we can figure out our bang for our buck.

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We can figure out, what is
going to be the marginal utility

00:02:20.252 --> 00:02:22.980
per dollar from that incremental bagel

00:02:22.980 --> 00:02:24.880
and that incremental toy car?

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And so we can, let's just explain first.

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So Theresa, Theresa will maximize,

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maximize her marginal utility

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per incremental dollar, per dollar,

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or let me put it this way, per dollar,

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when making purchases

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on the margin,

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making maybe, making purchases

00:02:58.720 --> 00:03:02.790
on the margin.

00:03:02.790 --> 00:03:05.440
So her next incremental purchase,

00:03:05.440 --> 00:03:08.803
her next incremental,

00:03:09.700 --> 00:03:13.150
incremental purchase.

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So we can write over here

00:03:15.730 --> 00:03:20.730
bagel marginal utility per dollar.

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That'll be one row here.

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And then we could write car

00:03:24.280 --> 00:03:28.940
or toy marginal utility per dollar.

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And then we set up these
rows right over here.

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And then we could think about
it if she for the first one,

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for the second one, for the third one,

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for the fourth one,

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let's see we go up to six, fifth one,

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and then we go to our sixth one.

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So let's start with bagels.

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Bagels cost $2.

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So that first bagel, if
she gets eight marginal

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utility units, well that's going to be

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four marginal utility units per dollar,

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eight divided by two.

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So that's four units per dollar,
and then that second bagel,

00:04:06.940 --> 00:04:09.260
she gets seven units but it costs $2,

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so it's seven divided
by two units per dollar.

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So that's going to be 3.5.

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And then six divided by two is three,

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five divided by two is 2.5,

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four divided by two is two.

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So that fifth bagel, two marginal
utility units per dollar,

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and then that sixth bagel,
three divided by two is 1.5

00:04:33.390 --> 00:04:35.120
marginal utility units per dollar.

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And now we can think about toys.

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Each toy is $1.

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So if she gets 10 marginal utility units

00:04:41.750 --> 00:04:44.200
from that first toy, it only cost her $1,

00:04:44.200 --> 00:04:46.300
so it's 10 utility units per dollar.

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So it's 10 there.

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It would be eight here.

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We're just dividing each of these by one.

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So six here, so this is gonna
be the same number again.

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Four, three, and two.

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So now that we set this
up, and let me scroll down

00:04:58.730 --> 00:05:00.240
a little bit so I have
a little bit more space.

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I have all the data I need.

00:05:02.040 --> 00:05:03.910
We can think about what
would be rational for her

00:05:03.910 --> 00:05:05.850
if we're thinking about
how she's gonna spend

00:05:05.850 --> 00:05:08.270
that $11 per week.

00:05:08.270 --> 00:05:10.803
Her first purchase, she's like wow,

00:05:10.803 --> 00:05:15.020
from the get go, that if I'm
picking between bagels and toys

00:05:15.020 --> 00:05:17.680
that first toy has a much
higher marginal utility

00:05:17.680 --> 00:05:19.420
per dollar than that first bagel.

00:05:19.420 --> 00:05:22.350
So she's going to start
here, and then she says,

00:05:22.350 --> 00:05:25.430
okay next do I wanna buy a bagel or a toy?

00:05:25.430 --> 00:05:28.620
But even that second toy, the
marginal utility per dollar

00:05:28.620 --> 00:05:30.980
is still higher than that first bagel.

00:05:30.980 --> 00:05:33.210
So then she'll buy a second toy.

00:05:33.210 --> 00:05:35.610
Then she'll think about it and
so far she's only spent $2,

00:05:35.610 --> 00:05:37.910
so we have a lot of money still left.

00:05:37.910 --> 00:05:40.130
Then she'll think about
okay, do I wanna spend

00:05:40.130 --> 00:05:42.640
that next incremental
amount on a toy or bagel?

00:05:42.640 --> 00:05:45.950
Well still, she gets more
marginal utility per dollar

00:05:45.950 --> 00:05:47.960
from the toy, so she'll spend that.

00:05:47.960 --> 00:05:50.203
She's spent $3 so far, $1, $2, $3.

00:05:51.960 --> 00:05:54.080
And now, when she thinks
about how to spend

00:05:54.080 --> 00:05:57.530
her next few dollars, she
says, well know I'm indifferent

00:05:57.530 --> 00:05:59.960
between bagels and toys.

00:05:59.960 --> 00:06:02.380
The marginal utility
per dollar is the same.

00:06:02.380 --> 00:06:06.345
So she might maybe spend
the next one on a toy

00:06:06.345 --> 00:06:10.430
and then right after that,
she'll go to bagels finally

00:06:10.430 --> 00:06:12.120
and buy a bagel.

00:06:12.120 --> 00:06:14.400
Well let's think about how
much she has spent so far.

00:06:14.400 --> 00:06:19.210
She's spent $4 on toys and $2 on bagels.

00:06:19.210 --> 00:06:23.740
So the order might look
something like this,

00:06:23.740 --> 00:06:28.110
and then she goes and
maybe buys her bagel.

00:06:28.110 --> 00:06:30.540
And now the marginal utility per dollar

00:06:30.540 --> 00:06:33.930
for that incremental
bagel is higher than for

00:06:33.930 --> 00:06:36.980
her next toy, and so
then she'll probably buy,

00:06:36.980 --> 00:06:39.000
she would buy another bagel right here,

00:06:39.000 --> 00:06:40.690
and let's see how much
money she has spent.

00:06:40.690 --> 00:06:44.960
Two bagels are $4 plus
she's spent $4 on toys

00:06:44.960 --> 00:06:46.160
because they're $1 each, so it's $8.

00:06:46.160 --> 00:06:48.390
So she still has $3 to spend.

00:06:48.390 --> 00:06:51.120
Now, her marginal utility
per dollar is neutral

00:06:51.120 --> 00:06:53.347
between bagels and toys,
between the incremental,

00:06:53.347 --> 00:06:55.790
the third bagel and that fifth toy,

00:06:55.790 --> 00:06:58.070
so she's indifferent between the two.

00:06:58.070 --> 00:07:00.000
So she could probably get both of them.

00:07:00.000 --> 00:07:02.530
So she might do something
like that, buy that,

00:07:02.530 --> 00:07:05.560
and then she could buy
that or she could do that

00:07:05.560 --> 00:07:06.400
in the other order.

00:07:06.400 --> 00:07:08.260
And let's see how much money she's spent.

00:07:08.260 --> 00:07:11.370
She has spent $5 on toys

00:07:11.370 --> 00:07:14.890
and she has spent $6 on bagels,

00:07:14.890 --> 00:07:17.730
and so she has spent her $11.

00:07:17.730 --> 00:07:20.020
And so to answer the first question,

00:07:20.020 --> 00:07:24.640
so she would buy,

00:07:24.640 --> 00:07:28.090
she would buy five toys,

00:07:28.090 --> 00:07:32.697
five toys, and three bagels,

00:07:34.950 --> 00:07:37.110
and three bagels

00:07:39.520 --> 00:07:44.520
based on this strategy of maximizing

00:07:52.040 --> 00:07:55.410
marginal utility per dollar

00:07:55.410 --> 00:08:00.410
for each incremental,
incremental purchase.

00:08:04.000 --> 00:08:05.720
Did I answer all of the questions?

00:08:05.720 --> 00:08:08.190
We said the quantity of bagels and toys

00:08:08.190 --> 00:08:10.900
that will maximize her marginal utility

00:08:10.900 --> 00:08:13.380
if she spends her weekly income,
and then we have explained

00:08:13.380 --> 00:08:14.610
using marginal analysis.

00:08:14.610 --> 00:08:15.810
Yep, we're looking good.


Scarcity and rivalry

WEBVTT
Kind: captions
Language: en

00:00:00.350 --> 00:00:01.183
- [Instructor] What we're going to do

00:00:01.183 --> 00:00:03.420
in this video is talk
about two related ideas

00:00:03.420 --> 00:00:06.380
that are really the
foundations of economics,

00:00:06.380 --> 00:00:10.810
the idea of scarcity
and the idea of rivalry.

00:00:10.810 --> 00:00:11.850
Now, in other videos,

00:00:11.850 --> 00:00:15.510
we do a deep dive into what scarcity is.

00:00:15.510 --> 00:00:17.920
But just as a review,
in everyday language,

00:00:17.920 --> 00:00:19.940
you could think of something is scarce,

00:00:19.940 --> 00:00:21.690
a good or a service is scarce

00:00:21.690 --> 00:00:23.610
if there's not enough for everyone.

00:00:23.610 --> 00:00:25.680
Another way to think about it is

00:00:25.680 --> 00:00:29.120
a scarce resource is one that is limited.

00:00:29.120 --> 00:00:31.533
It is a limited resource,

00:00:32.660 --> 00:00:34.620
and there's not enough to go around

00:00:34.620 --> 00:00:39.620
because there are potentially
unlimited wants from people,

00:00:39.870 --> 00:00:41.373
so potentially,

00:00:42.330 --> 00:00:45.373
potentially unlimited,

00:00:46.340 --> 00:00:47.460
unlimited wants.

00:00:47.460 --> 00:00:51.380
And we could think of a
lot of scarce resources.

00:00:51.380 --> 00:00:53.760
Oil would be a scarce resource.

00:00:53.760 --> 00:00:56.550
There's a limited supply of oil.

00:00:56.550 --> 00:01:00.160
And potentially, if oil were free,

00:01:00.160 --> 00:01:02.500
there's an unlimited amount of people

00:01:02.500 --> 00:01:04.110
who would want to use that oil.

00:01:04.110 --> 00:01:06.030
And so a lot of economics is, well,

00:01:06.030 --> 00:01:07.540
when you have a scarce resource,

00:01:07.540 --> 00:01:10.470
like oil or land or housing,

00:01:10.470 --> 00:01:14.030
how do you allocate those
resources amongst people,

00:01:14.030 --> 00:01:17.110
people who are demanding those resources?

00:01:17.110 --> 00:01:19.690
Now, rivalry is a related idea.

00:01:19.690 --> 00:01:23.450
When we think about the
everyday word rival or rivalry,

00:01:23.450 --> 00:01:26.760
you imagine multiple parties
competing for something,

00:01:26.760 --> 00:01:28.570
and that's essentially
getting pretty close

00:01:28.570 --> 00:01:30.770
to the economics definition of it.

00:01:30.770 --> 00:01:34.830
Something is a rival
good or a rival resource,

00:01:34.830 --> 00:01:37.320
I'll just call it a rival good right now,

00:01:37.320 --> 00:01:39.640
if, when one person uses it,

00:01:39.640 --> 00:01:42.550
it limits the ability for
other people to use it.

00:01:42.550 --> 00:01:44.390
So one,

00:01:44.390 --> 00:01:45.900
one person

00:01:47.140 --> 00:01:49.860
consuming it or using it,

00:01:49.860 --> 00:01:50.940
consuming it

00:01:51.890 --> 00:01:54.763
limits ability,

00:01:55.890 --> 00:01:57.290
ability

00:01:59.150 --> 00:02:00.780
for others,

00:02:00.780 --> 00:02:04.070
for others to use.

00:02:04.070 --> 00:02:06.730
And there's a lot of
examples of rival goods

00:02:06.730 --> 00:02:09.510
and things that are both
scarce and rival goods.

00:02:09.510 --> 00:02:13.780
For example, if I were to
put a nice, delicious cake

00:02:13.780 --> 00:02:15.930
that could only serve
four people in our office

00:02:15.930 --> 00:02:19.170
here at Khan Academy, where
we have 80 or 90 folks work,

00:02:19.170 --> 00:02:22.090
well, you can imagine, that
cake's going to be a rival good.

00:02:22.090 --> 00:02:25.210
It's also a scarce good
because many people,

00:02:25.210 --> 00:02:27.110
many more people are
gonna want that cake than

00:02:27.110 --> 00:02:28.610
the amount of cake we have.

00:02:28.610 --> 00:02:32.030
But when you look at what the
definition of a rival good is,

00:02:32.030 --> 00:02:34.270
every time I, if I eat the whole cake,

00:02:34.270 --> 00:02:37.850
that's going to limit other
people's ability to use it.

00:02:37.850 --> 00:02:41.540
And economists will sometimes
create a spectrum of

00:02:41.540 --> 00:02:44.500
how rivalrous a good is.

00:02:44.500 --> 00:02:48.440
So, for example, let me draw
a spectrum right over here.

00:02:48.440 --> 00:02:49.850
So on this line,

00:02:49.850 --> 00:02:53.500
so on the left-hand side, I
will call this highly rivalrous,

00:02:53.500 --> 00:02:55.370
which is, they'll actually use that word,

00:02:55.370 --> 00:02:58.550
but I'll just call this rival goods.

00:02:58.550 --> 00:03:02.940
And then at the other
extreme here, I'll say non,

00:03:02.940 --> 00:03:05.170
non-rival,

00:03:05.170 --> 00:03:07.190
non-rival good.

00:03:07.190 --> 00:03:08.630
And at the left end,

00:03:08.630 --> 00:03:12.060
it's pretty easy to come up
with a bunch of rival goods.

00:03:12.060 --> 00:03:15.820
If you're living in a place
where housing is tight,

00:03:15.820 --> 00:03:18.540
where all of the housing is taken up,

00:03:18.540 --> 00:03:21.620
housing is often a rival good.

00:03:21.620 --> 00:03:23.780
I live in the San Francisco Bay Area.

00:03:23.780 --> 00:03:26.640
And when a house goes on rent,
you'll have multiple people

00:03:26.640 --> 00:03:29.660
who are competing for that
house, or if it's going for sale.

00:03:29.660 --> 00:03:32.220
And so when one person gets
it and gets to live there,

00:03:32.220 --> 00:03:33.720
well, that's going to make it hard

00:03:33.720 --> 00:03:35.420
for other people to use it.

00:03:35.420 --> 00:03:37.990
You could imagine, you know, land

00:03:37.990 --> 00:03:41.200
in a lot of urban areas is a rival good.

00:03:41.200 --> 00:03:44.310
You could imagine something
like, you know, a cake,

00:03:44.310 --> 00:03:46.560
especially if there's not
a lot of cake to go around

00:03:46.560 --> 00:03:48.240
at a birthday party.

00:03:48.240 --> 00:03:49.860
Now, what would be the other extreme?

00:03:49.860 --> 00:03:53.020
What would be a non-rival good?

00:03:53.020 --> 00:03:56.580
Well, there are very few
perfectly non-rival goods,

00:03:56.580 --> 00:03:58.080
but there are things that are close to it.

00:03:58.080 --> 00:04:01.060
Because at least relative
to where people's,

00:04:01.060 --> 00:04:02.860
where people are trying to use it today,

00:04:02.860 --> 00:04:06.840
it seems like there's almost
an unlimited supply of it.

00:04:06.840 --> 00:04:09.070
One example might be
something that's close.

00:04:09.070 --> 00:04:10.740
I'm not gonna put it
all the way at the end.

00:04:10.740 --> 00:04:12.740
I'm gonna put air,

00:04:12.740 --> 00:04:15.040
air to breathe

00:04:15.040 --> 00:04:16.130
on Earth.

00:04:16.130 --> 00:04:17.630
Now, right now it's a non-rival good.

00:04:17.630 --> 00:04:20.640
When I take a deep breath,
it doesn't make it hard

00:04:20.640 --> 00:04:23.170
for you to take another
simultaneous deep breath.

00:04:23.170 --> 00:04:25.320
And actually, let me put
a little qualifier here,

00:04:25.320 --> 00:04:27.110
simultaneously,

00:04:27.110 --> 00:04:29.720
simultaneously.

00:04:29.720 --> 00:04:32.800
That's actually a key
qualifier for a rival good.

00:04:32.800 --> 00:04:36.480
So, for example, a hammer
is also a rival good.

00:04:36.480 --> 00:04:39.120
Because if I'm using it right now,

00:04:39.120 --> 00:04:43.120
it becomes very hard for you
to use it simultaneously.

00:04:43.120 --> 00:04:44.670
Now, as I mentioned, air to breathe,

00:04:44.670 --> 00:04:46.430
if I take a deep breath right now,

00:04:46.430 --> 00:04:49.630
it doesn't make it any harder
for you to take a deep breath.

00:04:49.630 --> 00:04:52.460
But if you were to take a
extreme circumstance that,

00:04:52.460 --> 00:04:53.900
let's say that if we were in a closed room

00:04:53.900 --> 00:04:56.500
with a limited supply of
oxygen, well, then the air

00:04:56.500 --> 00:04:58.940
might become something
closer to a rival good.

00:04:58.940 --> 00:05:01.440
So let me put it this way,
air to breathe outside,

00:05:02.930 --> 00:05:06.640
while here I'll put air in

00:05:06.640 --> 00:05:10.140
airtight, or let me put oxygen
in an airtight container

00:05:10.140 --> 00:05:11.790
or airtight room,

00:05:11.790 --> 00:05:13.480
oxygen

00:05:13.480 --> 00:05:16.090
in airtight

00:05:17.050 --> 00:05:19.750
room or maybe a room that
is running out of oxygen.

00:05:19.750 --> 00:05:21.730
Well, then every time I take
a breath, it's gonna make it

00:05:21.730 --> 00:05:24.840
harder for you to take
a breath and vice versa.

00:05:24.840 --> 00:05:29.050
There's other things like,
well, roads are rival goods,

00:05:29.050 --> 00:05:31.450
especially if we're
talking about rush hour.

00:05:31.450 --> 00:05:33.460
So let me put this right over here.

00:05:33.460 --> 00:05:37.290
So let's call this the
roads during rush hour,

00:05:37.290 --> 00:05:38.780
roads during

00:05:39.920 --> 00:05:41.260
rush hour.

00:05:41.260 --> 00:05:43.080
The more people that are on the roads,

00:05:43.080 --> 00:05:44.090
that it's gonna make it harder

00:05:44.090 --> 00:05:46.800
for other people to use it simultaneously.

00:05:46.800 --> 00:05:47.740
It will get all this traffic.

00:05:47.740 --> 00:05:49.300
People won't even be able
to get on the highway 'cause

00:05:49.300 --> 00:05:51.440
there's so much gridlock.

00:05:51.440 --> 00:05:52.850
But then you could imagine roads

00:05:52.850 --> 00:05:54.860
in the middle of the
night are non-rival goods.

00:05:54.860 --> 00:05:56.020
If I decide to take a drive

00:05:56.020 --> 00:05:57.900
at three in the morning on most highways,

00:05:57.900 --> 00:06:01.050
it doesn't make it any
harder for another person

00:06:01.050 --> 00:06:03.030
to take a drive on that
highway simultaneously.

00:06:03.030 --> 00:06:06.060
So let me put it over here, roads,

00:06:06.060 --> 00:06:09.220
roads at 3:00 a.m.

00:06:09.220 --> 00:06:14.220
in most places is closer
to being a non-rival good.

00:06:14.240 --> 00:06:15.680
So I will leave you there.

00:06:15.680 --> 00:06:16.850
These are ideas that we're going

00:06:16.850 --> 00:06:18.890
to keep revisiting in economics.

00:06:18.890 --> 00:06:21.660
But it's good to have a
sense of what they mean,

00:06:21.660 --> 00:06:24.050
and then it'll inform how we think about

00:06:24.050 --> 00:06:26.320
allocating these scarce
goods amongst folks

00:06:26.320 --> 00:06:28.270
and thinking about how we allocate

00:06:28.270 --> 00:06:30.753
these rival goods amongst various parties.


Introduction to one-dimensional motion with calculus

WEBVTT
Kind: captions
Language: en

00:00:00.290 --> 00:00:01.123
- [Instructor] What we're going to do

00:00:01.123 --> 00:00:02.610
in this video is start to think about

00:00:02.610 --> 00:00:05.550
how we describe position in one dimension

00:00:05.550 --> 00:00:06.770
as a function of time.

00:00:06.770 --> 00:00:07.920
So we could say our position,

00:00:07.920 --> 00:00:09.320
and we're gonna think about position

00:00:09.320 --> 00:00:11.990
on the x-axis as a function of time.

00:00:11.990 --> 00:00:13.720
And we could define it by some expression,

00:00:13.720 --> 00:00:15.330
let's say, in this situation,

00:00:15.330 --> 00:00:17.930
it is going to be our
time to the third power

00:00:17.930 --> 00:00:21.570
minus three times our
time squared plus five.

00:00:21.570 --> 00:00:22.760
And this is going to apply

00:00:22.760 --> 00:00:25.890
for our time being non-negative

00:00:25.890 --> 00:00:27.220
'cause the idea of negative time,

00:00:27.220 --> 00:00:29.640
at least for now, is a bit strange.

00:00:29.640 --> 00:00:31.310
So let's think about what this

00:00:31.310 --> 00:00:32.880
right over here is describing.

00:00:32.880 --> 00:00:34.360
And to help us do that,

00:00:34.360 --> 00:00:36.640
we could set up a little bit of a table

00:00:36.640 --> 00:00:39.510
to understand that depending
on what time we are,

00:00:39.510 --> 00:00:41.680
let's say that time is in seconds,

00:00:41.680 --> 00:00:45.140
what is going to be our
position along our x-axis?

00:00:45.140 --> 00:00:50.140
So at time equals zero, x of
zero is just going to be five.

00:00:50.170 --> 00:00:55.170
At time one, you're gonna have
one minus three plus five.

00:00:55.430 --> 00:00:57.040
So that is going to be,

00:00:57.040 --> 00:01:00.200
let's see, one minus
three is negative two,

00:01:00.200 --> 00:01:02.330
plus five is going to be,

00:01:02.330 --> 00:01:04.090
we're going to be at position three.

00:01:04.090 --> 00:01:07.550
And then at time two, we are going to be

00:01:07.550 --> 00:01:11.030
at eight minus 12 plus five,

00:01:11.030 --> 00:01:12.950
so we're going to be at position one.

00:01:12.950 --> 00:01:15.660
And then at time t equals three,

00:01:15.660 --> 00:01:18.570
it's gonna be 27 minus 27 plus five,

00:01:18.570 --> 00:01:20.360
we're gonna be back at five.

00:01:20.360 --> 00:01:22.530
And so, this can at
least help us understand

00:01:22.530 --> 00:01:25.540
what's going on for the
first three seconds.

00:01:25.540 --> 00:01:29.370
So let me draw our positive x-axis.

00:01:29.370 --> 00:01:32.990
So, say it looks something like that.

00:01:34.300 --> 00:01:37.170
And this is x equals zero.

00:01:37.170 --> 00:01:38.230
This is our x-axis.

00:01:38.230 --> 00:01:43.230
X equals one, two, three, four, and five.

00:01:45.390 --> 00:01:49.260
And now let's play out how this particle

00:01:49.260 --> 00:01:51.560
that's being described is
moving along the x-axis.

00:01:51.560 --> 00:01:53.150
So we're gonna start here,

00:01:53.150 --> 00:01:58.150
and we're gonna go one, two, three.

00:01:58.190 --> 00:01:59.470
Let's do it again.

00:01:59.470 --> 00:02:03.460
We're going to go one, two, three,

00:02:03.460 --> 00:02:06.110
the way I just moved
my mouse, if we assume

00:02:06.110 --> 00:02:07.730
that I got the time roughly right,

00:02:07.730 --> 00:02:09.800
is how that particle would move.

00:02:09.800 --> 00:02:11.960
And we can graph this as well.

00:02:12.810 --> 00:02:16.740
So for example, it would look like this.

00:02:16.740 --> 00:02:20.260
We are starting at time t equals zero.

00:02:20.260 --> 00:02:23.620
Our position, this is our
vertical axis, our y-axis,

00:02:23.620 --> 00:02:25.750
but we're just saying
y is going to be equal

00:02:25.750 --> 00:02:28.000
to our position along the x-axis.

00:02:28.000 --> 00:02:29.500
So that's a little bit counterintuitive

00:02:29.500 --> 00:02:31.600
because we're talking about our position

00:02:31.600 --> 00:02:33.260
in the left-right dimension,

00:02:33.260 --> 00:02:34.920
and here you're seeing it start off

00:02:34.920 --> 00:02:36.230
in the vertical dimension,

00:02:36.230 --> 00:02:37.670
but you see the same thing.

00:02:37.670 --> 00:02:41.520
At time t equals one, our
position has gone down to three.

00:02:41.520 --> 00:02:43.050
Then it goes down further.

00:02:43.050 --> 00:02:46.400
At time equals two, our
position is down to one.

00:02:46.400 --> 00:02:48.550
And then, we switch direction

00:02:48.550 --> 00:02:51.110
and then over the next, if we
say that time is in seconds,

00:02:51.110 --> 00:02:54.390
over the next second, we get back to five.

00:02:54.390 --> 00:02:55.990
Now an interesting thing to think about

00:02:55.990 --> 00:02:57.870
in the context of calculus is,

00:02:57.870 --> 00:03:00.220
well, what is our velocity
at any point in time?

00:03:00.220 --> 00:03:02.310
And velocity as you might remember,

00:03:02.310 --> 00:03:05.510
is the derivative of position.

00:03:05.510 --> 00:03:06.950
So let me write that down.

00:03:06.950 --> 00:03:09.560
So we're gonna be thinking about velocity

00:03:09.560 --> 00:03:11.030
as a function of time.

00:03:11.030 --> 00:03:13.140
And you could view velocity
as the first derivative

00:03:13.140 --> 00:03:15.280
of position with respect to time

00:03:15.280 --> 00:03:16.500
which is just going to be equal to,

00:03:16.500 --> 00:03:18.040
or we're gonna apply the power rule

00:03:18.040 --> 00:03:19.860
and some derivative
properties multiple times.

00:03:19.860 --> 00:03:21.800
If this is unfamiliar to you,

00:03:21.800 --> 00:03:23.460
I encourage you to review it.

00:03:23.460 --> 00:03:25.990
But this is going to be three t squared

00:03:25.990 --> 00:03:29.460
minus six t and then plus zero,

00:03:29.460 --> 00:03:33.580
and we're gonna restrict
the domain as well for t

00:03:33.580 --> 00:03:35.560
is greater than or equal to zero.

00:03:35.560 --> 00:03:38.220
And then, we can plot that.

00:03:38.220 --> 00:03:39.480
It would look like that.

00:03:40.590 --> 00:03:44.530
Now let's see if this curve
makes intuitive sense.

00:03:44.530 --> 00:03:47.320
We mentioned that one second, two seconds,

00:03:47.320 --> 00:03:48.670
three seconds.

00:03:48.670 --> 00:03:50.990
So we're starting moving to the left.

00:03:50.990 --> 00:03:52.950
And the convention is if
you're moving to the left,

00:03:52.950 --> 00:03:54.080
you have negative velocity,

00:03:54.080 --> 00:03:54.970
and if you're moving to the right,

00:03:54.970 --> 00:03:56.530
you have positive velocity.

00:03:56.530 --> 00:03:58.370
And you can see here our velocity

00:03:58.370 --> 00:04:00.140
immediately gets more and more negative

00:04:00.140 --> 00:04:01.610
until we get to one second,

00:04:01.610 --> 00:04:03.420
and then it stays negative
but it's getting less

00:04:03.420 --> 00:04:06.250
and less negative until
we get to two seconds.

00:04:06.250 --> 00:04:08.860
And at two seconds, our
velocity becomes positive.

00:04:08.860 --> 00:04:10.770
And that makes sense,
because at two seconds

00:04:10.770 --> 00:04:12.790
was when our velocity switched directions

00:04:12.790 --> 00:04:14.400
to the rightward direction.

00:04:14.400 --> 00:04:18.030
So, our velocity is getting
more and more negative,

00:04:18.030 --> 00:04:20.670
less and less negative, and
then we switch directions

00:04:20.670 --> 00:04:22.140
and we go just like that.

00:04:22.140 --> 00:04:24.020
And we see it right over here.

00:04:24.020 --> 00:04:25.530
Now one thing to keep in mind

00:04:25.530 --> 00:04:28.390
when we're thinking about
velocity as a function of time

00:04:28.390 --> 00:04:31.620
is that velocity and speed
are two different things.

00:04:31.620 --> 00:04:34.040
Speed, speed, let me write it over here.

00:04:34.040 --> 00:04:36.830
Speed is equal to, if you think about it

00:04:36.830 --> 00:04:38.180
in one dimension, you could think about it

00:04:38.180 --> 00:04:40.310
as the absolute value of your velocity

00:04:40.310 --> 00:04:43.140
as a function of time or
your magnitude of velocity

00:04:43.140 --> 00:04:44.740
as a function of time.

00:04:44.740 --> 00:04:46.660
So in the beginning,
even though your velocity

00:04:46.660 --> 00:04:48.940
is becoming more and more negative,

00:04:48.940 --> 00:04:50.680
your speed is actually increasing.

00:04:50.680 --> 00:04:52.780
Your speed is increasing to the left,

00:04:52.780 --> 00:04:54.440
then your speed is
decreasing, you slow down,

00:04:54.440 --> 00:04:56.110
and then your speed is increasing

00:04:56.110 --> 00:04:57.300
as we go to the right.

00:04:57.300 --> 00:04:58.930
And we'll do some worked examples

00:04:58.930 --> 00:05:01.090
that work through that a little bit more.

00:05:01.090 --> 00:05:03.710
Now the last concept we
will touch on in this video

00:05:03.710 --> 00:05:05.490
is the idea of acceleration.

00:05:05.490 --> 00:05:06.570
And acceleration you can view

00:05:06.570 --> 00:05:09.360
as the rate of change of
velocity with respect to time.

00:05:09.360 --> 00:05:11.560
So acceleration as a function of time

00:05:11.560 --> 00:05:13.450
is just going to be the first derivative

00:05:13.450 --> 00:05:15.300
of velocity with respect to time

00:05:15.300 --> 00:05:16.910
which is equal to the second derivative

00:05:16.910 --> 00:05:18.330
of position with respect to time.

00:05:18.330 --> 00:05:20.330
It's just going to be the
derivative of this expression.

00:05:20.330 --> 00:05:22.310
So once again, using the power rule here,

00:05:22.310 --> 00:05:23.300
that's going to be six t.

00:05:23.300 --> 00:05:25.120
And then using the power rule here,

00:05:25.120 --> 00:05:29.700
minus six, and once again,
we will restrict the domain.

00:05:29.700 --> 00:05:32.380
And we can graph that as well.

00:05:33.290 --> 00:05:34.660
And we would see right over here,

00:05:34.660 --> 00:05:38.190
this is y is equal to acceleration
as a function of time.

00:05:38.190 --> 00:05:39.900
And you can see at time equals zero,

00:05:39.900 --> 00:05:41.510
our acceleration is quite negative.

00:05:41.510 --> 00:05:43.280
It is negative six.

00:05:43.280 --> 00:05:46.190
And then it becomes less
and less and less negative.

00:05:46.190 --> 00:05:47.830
And then, our acceleration actually

00:05:47.830 --> 00:05:49.480
becomes positive at t equals one.

00:05:49.480 --> 00:05:51.060
Now, does that makes sense?

00:05:51.060 --> 00:05:54.010
Well, we're going one, two, three.

00:05:54.010 --> 00:05:55.780
You might say, "Wait, we
didn't switch directions

00:05:55.780 --> 00:05:57.650
"until we get to the second second."

00:05:57.650 --> 00:05:59.980
But remember, after we
get to the first second,

00:05:59.980 --> 00:06:03.770
our velocity in the negative direction

00:06:03.770 --> 00:06:06.040
becomes less negative which means

00:06:06.040 --> 00:06:09.050
that our acceleration is positive.

00:06:09.050 --> 00:06:09.930
If that's a little confusing,

00:06:09.930 --> 00:06:12.010
pause the video and
really think through that.

00:06:12.010 --> 00:06:14.470
So, our acceleration is
negative, then positive,

00:06:14.470 --> 00:06:16.870
and then positive continues.

00:06:16.870 --> 00:06:18.390
And so, this is just to
give you an intuition.

00:06:18.390 --> 00:06:20.580
In the next few videos, we'll
do several worked examples

00:06:20.580 --> 00:06:22.860
that help us dive deeper into this idea

00:06:22.860 --> 00:06:25.650
of studying motion and position,

00:06:26.630 --> 00:06:29.560
into this idea of studying
motion in one dimension.


The media and partisanship

WEBVTT
Kind: captions
Language: en

00:00:00.540 --> 00:00:02.360
- So John, when our nation was founded

00:00:02.360 --> 00:00:03.230
there was media.

00:00:03.230 --> 00:00:05.190
It was essentially newspapers.

00:00:05.190 --> 00:00:08.780
How has the evolution of media affected

00:00:08.780 --> 00:00:11.020
the evolution of political discourse?

00:00:11.020 --> 00:00:12.530
- At the beginning of our country

00:00:12.530 --> 00:00:14.710
the editors of the rival newspapers,

00:00:14.710 --> 00:00:16.580
there was no middle of the road newspaper,

00:00:16.580 --> 00:00:19.620
you were either for one or the other,

00:00:19.620 --> 00:00:20.880
you were either a Federalist

00:00:20.880 --> 00:00:25.880
or you were the Jeffersonian
Democratic Republicans,

00:00:25.950 --> 00:00:27.711
as they called themselves,

00:00:27.711 --> 00:00:30.310
and the editors were at each
others throat so violently,

00:00:30.310 --> 00:00:32.580
they would sometimes get
in fights in the street

00:00:32.580 --> 00:00:34.223
and knock each other down.

00:00:35.435 --> 00:00:37.720
And you had lawmakers who were supposed

00:00:37.720 --> 00:00:40.470
to be men of virtue as
all men in those days

00:00:40.470 --> 00:00:42.903
would be leaking documents.

00:00:42.903 --> 00:00:44.210
Alexander Hamilton,
the Treasury Secretary,

00:00:44.210 --> 00:00:46.470
and Thomas Jefferson,
the Secretary of State,

00:00:46.470 --> 00:00:48.770
would leak documents to
their favorite papers

00:00:48.770 --> 00:00:50.500
in order to attack the other.

00:00:50.500 --> 00:00:52.540
And eventually George
Washington had to come in

00:00:52.540 --> 00:00:54.900
and say knock it off fellas,

00:00:54.900 --> 00:00:57.300
because this isn't good for the country.

00:00:57.300 --> 00:00:59.420
So the bitterness carried out in the press

00:00:59.420 --> 00:01:01.310
was with us from the founding.

00:01:01.310 --> 00:01:04.680
What changed over time is
that it became interestedly,

00:01:04.680 --> 00:01:08.480
newspaper particularly, to
appeal to a larger audience.

00:01:08.480 --> 00:01:10.520
That means you didn't want
just the left or the right.

00:01:10.520 --> 00:01:11.900
You wanted both.

00:01:11.900 --> 00:01:15.340
So that created a tradition,
along with a few other things,

00:01:15.340 --> 00:01:17.720
where there was an attempt
to give just the facts,

00:01:17.720 --> 00:01:19.900
a kind of middle of the road perspective.

00:01:19.900 --> 00:01:21.350
We are changing from that now,

00:01:21.350 --> 00:01:24.180
where the economics of covering the news

00:01:24.180 --> 00:01:27.870
and the digital change
where you now can have

00:01:27.870 --> 00:01:31.180
anybody speaking and
gaining access to the public

00:01:31.180 --> 00:01:32.980
has created a situation where you have

00:01:32.980 --> 00:01:34.500
a more partisan press now,

00:01:34.500 --> 00:01:36.100
and we're in the middle
of trying to figure out

00:01:36.100 --> 00:01:37.280
where that's going next.

00:01:37.280 --> 00:01:38.770
- This is interesting
because a lot of people

00:01:38.770 --> 00:01:41.050
when they talk about well,
not it's getting polarized

00:01:41.050 --> 00:01:44.210
and partisan, the good ol'
days when you got the truth,

00:01:44.210 --> 00:01:46.950
the wisdom from Walter
Cronkite or whoever,

00:01:46.950 --> 00:01:49.390
but what you're really
talking about is maybe

00:01:49.390 --> 00:01:51.500
what's going on now is a
little bit of a reversion

00:01:51.500 --> 00:01:53.270
back to where we started.

00:01:53.270 --> 00:01:54.103
- That's right.

00:01:54.103 --> 00:01:55.450
In terms of the partisanship of the press

00:01:55.450 --> 00:01:58.290
it is a reversion towards
the early days of America,

00:01:58.290 --> 00:02:01.570
and in terms of the partisanship
of the individual members

00:02:01.570 --> 00:02:04.580
of Congress or of the White House.

00:02:04.580 --> 00:02:09.120
What is a little bit different
is that the call to virtue,

00:02:09.120 --> 00:02:12.363
which would snap people
out of their partisanship,

00:02:14.460 --> 00:02:16.076
is still up for grabs.

00:02:16.076 --> 00:02:19.110
The founders, when they
fought like cats and dogs

00:02:19.110 --> 00:02:21.530
during the early years
of the administrations,

00:02:21.530 --> 00:02:24.230
Thomas Jefferson was best
friends with John Adams,

00:02:24.230 --> 00:02:27.600
and essentially then
hired a newspaper writer

00:02:27.600 --> 00:02:29.540
to undermine Adams when he was president.

00:02:29.540 --> 00:02:31.980
I mean, this was a very dirty pool.

00:02:31.980 --> 00:02:35.110
The argument they were making
was our country is new,

00:02:35.110 --> 00:02:37.680
and what is at stake is the very survival

00:02:37.680 --> 00:02:39.150
of the American experiment.

00:02:39.150 --> 00:02:41.310
So they were fighting for real stakes.

00:02:41.310 --> 00:02:44.870
They weren't just trying
to primarily keep power.

00:02:44.870 --> 00:02:47.430
They were really trying
to make this flower bloom

00:02:47.430 --> 00:02:49.020
that they had just planted.

00:02:49.020 --> 00:02:52.050
So now the question is
what role does virtue play

00:02:52.050 --> 00:02:55.150
in the American experience
to pull people away

00:02:55.150 --> 00:02:56.510
from their partisanship?

00:02:56.510 --> 00:02:59.610
To make them work together
for common interests?

00:02:59.610 --> 00:03:01.970
And what is that shared
area of common interest?

00:03:01.970 --> 00:03:03.660
What pulls them away from,

00:03:03.660 --> 00:03:06.040
what the founders knew,
people would behave like dogs

00:03:06.040 --> 00:03:08.530
sometimes, but they thought
they could pull away

00:03:08.530 --> 00:03:10.160
if they thought about the common interest.

00:03:10.160 --> 00:03:11.910
Well, is that pull still there?

00:03:11.910 --> 00:03:14.620
- So there's a lot of talk
these days about polarization

00:03:14.620 --> 00:03:17.240
of the media or polarization
of politics in general.

00:03:17.240 --> 00:03:19.580
How much of it do you
think is due to things

00:03:19.580 --> 00:03:21.910
like social media, or do
you think it was inevitable?

00:03:21.910 --> 00:03:24.730
- We've always had polarization
in American politics,

00:03:24.730 --> 00:03:26.290
but there was a dose of something else,

00:03:26.290 --> 00:03:28.950
which was a call to a
higher American ideal.

00:03:28.950 --> 00:03:33.950
And also voters would vote on
people based on their virtue,

00:03:33.960 --> 00:03:38.120
on their larger than life statesmanship,

00:03:38.120 --> 00:03:39.260
which was not partisan.

00:03:39.260 --> 00:03:40.780
So you had to keep a balance.

00:03:40.780 --> 00:03:42.290
If you were being highly partisan,

00:03:42.290 --> 00:03:43.910
you kinda did it in quiet.

00:03:43.910 --> 00:03:46.560
What's changed now with
social media and also

00:03:46.560 --> 00:03:49.800
with the flood of money
in politics is that

00:03:49.800 --> 00:03:53.060
it has encouraged people to
be more and more partisan.

00:03:53.060 --> 00:03:55.820
The louder and hotter I
talk on a specific issue

00:03:55.820 --> 00:03:57.420
the more money I'm gonna be able to raise,

00:03:57.420 --> 00:03:59.060
the more interest groups
are gonna like me,

00:03:59.060 --> 00:04:00.530
and the more clicks I'm gonna get

00:04:00.530 --> 00:04:03.330
because I'm the one making
the most flamboyant noise.

00:04:03.330 --> 00:04:05.090
The problem is that means the arguments

00:04:05.090 --> 00:04:07.330
are always containing flamboyant noise.

00:04:07.330 --> 00:04:11.600
And the people who want a calm
steady measured conversation,

00:04:11.600 --> 00:04:14.090
well, they're not getting
read on social media.

00:04:14.090 --> 00:04:15.900
They're not in charge
of the interest groups

00:04:15.900 --> 00:04:18.140
that pay millions and millions of dollars.

00:04:18.140 --> 00:04:21.970
So the system encourages
people to stay apart,

00:04:21.970 --> 00:04:24.320
and that's one of the biggest challenges

00:04:24.320 --> 00:04:26.960
Secretary of Defense, James Mattis,

00:04:26.960 --> 00:04:29.830
says it may be the greatest
threat to American democracy,

00:04:29.830 --> 00:04:31.730
that polarization.

00:04:31.730 --> 00:04:34.500
- Do you see a way of
this getting resolved?

00:04:34.500 --> 00:04:35.510
Or does it get worse?

00:04:35.510 --> 00:04:36.343
Does it get better?

00:04:36.343 --> 00:04:37.730
- There have been periods
of American history

00:04:37.730 --> 00:04:38.930
where we have been this split.

00:04:38.930 --> 00:04:42.750
Obviously the Civil War was
a period of great rending

00:04:42.750 --> 00:04:44.410
in the American fabric.

00:04:44.410 --> 00:04:47.639
What changed it was an actual conflict.

00:04:47.639 --> 00:04:51.660
So that, God forbid,
would be one way to do it.

00:04:51.660 --> 00:04:53.610
Another would be if there
was a threat to America

00:04:53.610 --> 00:04:55.650
from outside its borders
and people would feel

00:04:55.650 --> 00:04:59.730
an acute sense of national
pride and patriotism.

00:04:59.730 --> 00:05:03.430
But other than that there doesn't appear

00:05:03.430 --> 00:05:05.910
to be at the moment a quick fix for what

00:05:05.910 --> 00:05:09.220
is a complicated problem
for why the two parties

00:05:09.220 --> 00:05:13.240
have gotten into a inescapable fight

00:05:13.240 --> 00:05:15.170
that they can't seem to
get themselves out of.

00:05:15.170 --> 00:05:17.610
- It's like we need a
shock to remind ourselves

00:05:17.610 --> 00:05:19.300
how much commonality there is

00:05:19.300 --> 00:05:21.900
so all of the polarizing
quibbling goes away,

00:05:21.900 --> 00:05:23.530
or at least gets covered up a little bit.

00:05:23.530 --> 00:05:24.880
- Big changes in American history

00:05:24.880 --> 00:05:27.260
usually happen from a shock and it's what

00:05:27.260 --> 00:05:29.010
breaks people out of their behavior,

00:05:29.010 --> 00:05:31.730
and also which tells a lot of the people

00:05:31.730 --> 00:05:33.560
in the rest of the country
who don't participate

00:05:33.560 --> 00:05:35.440
in presidential elections
and don't participate

00:05:35.440 --> 00:05:36.810
in congressional elections,

00:05:36.810 --> 00:05:39.470
it reminds them that
something real is at stake.

00:05:39.470 --> 00:05:41.700
And there is a vast group of Americans

00:05:41.700 --> 00:05:43.900
who really want solutions in the middle,

00:05:43.900 --> 00:05:46.900
who don't care about the
bickering and the ideology.

00:05:46.900 --> 00:05:49.140
But a lot of them don't
participate in politics.

00:05:49.140 --> 00:05:52.420
And so the kind of shock
that would make people

00:05:52.420 --> 00:05:54.760
behave who are partisans
is also the kind of shock

00:05:54.760 --> 00:05:57.770
that would draw in people
who are just apathetic

00:05:57.770 --> 00:06:00.070
and not participating
in the political system.


Changes to the role of the presidency

WEBVTT
Kind: captions
Language: en

00:00:00.430 --> 00:00:03.360
- So, John, how has the role
of the presidency changed

00:00:03.360 --> 00:00:06.060
over the last several hundreds of years?

00:00:06.060 --> 00:00:08.140
- It's changed dramatically.

00:00:08.140 --> 00:00:09.760
First of all, when the founders created

00:00:09.760 --> 00:00:11.540
the presidency, they left it kinda loose.

00:00:11.540 --> 00:00:13.140
They weren't exactly very specific

00:00:13.140 --> 00:00:14.520
about what a president would do.

00:00:14.520 --> 00:00:16.400
And they realized that
the first president,

00:00:16.400 --> 00:00:18.570
George Washington, and this
is why he was so important,

00:00:18.570 --> 00:00:21.640
was a man of virtue and
that he in his behavior

00:00:21.640 --> 00:00:24.710
would set the precedence for
the next president after him.

00:00:24.710 --> 00:00:27.590
That means the job is basically
handed off by tradition

00:00:27.590 --> 00:00:29.087
from president to
president but that also--

00:00:29.087 --> 00:00:30.680
- And the reason why they
didn't know what a president

00:00:30.680 --> 00:00:32.830
should do is that there
wasn't a notion of a,

00:00:32.830 --> 00:00:34.720
there wasn't a precedent
for being a president.

00:00:34.720 --> 00:00:36.000
- That's right, they knew
what they didn't want.

00:00:36.000 --> 00:00:38.050
They didn't want two things,
they didn't want a king,

00:00:38.050 --> 00:00:39.450
they'd just gotten rid of one of those.

00:00:39.450 --> 00:00:41.080
They didn't want a king
and they also didn't

00:00:41.080 --> 00:00:44.333
want somebody who's
whipped around by mob rule.

00:00:45.200 --> 00:00:46.220
Those were the two things they were

00:00:46.220 --> 00:00:47.300
trying to get between.

00:00:47.300 --> 00:00:49.150
But, a president has a lot of room

00:00:49.150 --> 00:00:50.290
to move in between the two of them,

00:00:50.290 --> 00:00:51.123
and they thought we'll put it

00:00:51.123 --> 00:00:53.150
in the hands of a virtuous American.

00:00:53.150 --> 00:00:55.640
George Washington, a good
first virtuous American,

00:00:55.640 --> 00:00:58.440
and that person, through
their virtue and character,

00:00:58.440 --> 00:00:59.850
would stay in the right place.

00:00:59.850 --> 00:01:02.940
Would not become a king and
would not give over to the mob,

00:01:02.940 --> 00:01:04.480
but it also meant that it relied

00:01:04.480 --> 00:01:06.330
on the character of the
person in the presidency.

00:01:06.330 --> 00:01:08.981
And so, each president
in subsequent years,

00:01:08.981 --> 00:01:12.080
has taken shape in the presidency both

00:01:12.080 --> 00:01:13.740
by what was determined
by their predecessors,

00:01:13.740 --> 00:01:16.340
but also by what they could do in the job.

00:01:16.340 --> 00:01:18.410
And what's happened is,
a job that started out

00:01:18.410 --> 00:01:20.780
very weak in the American system has now

00:01:20.780 --> 00:01:23.420
become one where some people think of all

00:01:23.420 --> 00:01:26.100
the entire of American
government as the president.

00:01:26.100 --> 00:01:28.330
And that's not what the founders wanted.

00:01:28.330 --> 00:01:29.320
- But how does that evolve?

00:01:29.320 --> 00:01:32.140
'Cause obviously the constitution talks

00:01:32.140 --> 00:01:33.680
about the powers of the president.

00:01:33.680 --> 00:01:36.030
So, how does it change so much over time?

00:01:36.030 --> 00:01:37.510
- What happened was, when they originally

00:01:37.510 --> 00:01:39.200
created the presidency there was a debate,

00:01:39.200 --> 00:01:42.130
and the debate was, we need
somebody who can move quickly.

00:01:42.130 --> 00:01:44.010
We can't always be calling
them in to Congress

00:01:44.010 --> 00:01:45.000
because, of course, when the America

00:01:45.000 --> 00:01:46.790
was started they used
to take several months,

00:01:46.790 --> 00:01:48.140
or sometimes it would take weeks

00:01:48.140 --> 00:01:50.010
to get on a horse and get to Washington.

00:01:50.010 --> 00:01:52.500
So, we need an executive
who can move quickly.

00:01:52.500 --> 00:01:55.610
Well, what happened was, in various wars,

00:01:55.610 --> 00:01:57.070
America needed to move quickly,

00:01:57.070 --> 00:01:58.660
and they needed one person to act

00:01:58.660 --> 00:02:00.490
on behalf of the entire Union.

00:02:00.490 --> 00:02:02.830
Well, there's only one
person who can do that.

00:02:02.830 --> 00:02:06.300
But, as people wanted
quick action they handed

00:02:06.300 --> 00:02:07.800
over more power to the president.

00:02:07.800 --> 00:02:10.520
Congress, which used to fight
with the president a lot,

00:02:10.520 --> 00:02:11.730
during the Second World War

00:02:11.730 --> 00:02:13.520
and then on into our present day,

00:02:13.520 --> 00:02:15.570
has given up a lot of its
power to the president.

00:02:15.570 --> 00:02:18.150
One of the key ones being
the power to make war.

00:02:18.150 --> 00:02:19.680
Presidents can now go and make war.

00:02:19.680 --> 00:02:21.710
Well, that's not the
original way it was arranged.

00:02:21.710 --> 00:02:24.090
And they've done it
because there is a hunger

00:02:24.090 --> 00:02:25.990
in the country for quick action,

00:02:25.990 --> 00:02:27.910
but the problem and challenge of that is,

00:02:27.910 --> 00:02:30.130
if you invest somebody in with power

00:02:30.130 --> 00:02:32.590
to do things quickly in an emergency,

00:02:32.590 --> 00:02:35.300
they hold on to that power
and they don't let it go,

00:02:35.300 --> 00:02:36.620
and that means that they start

00:02:36.620 --> 00:02:38.960
doing things when it's not an emergency,

00:02:38.960 --> 00:02:41.540
that is then not vetted
by the American system.

00:02:41.540 --> 00:02:43.760
And that system has both the judiciary

00:02:43.760 --> 00:02:45.630
and the legislative which are meant

00:02:45.630 --> 00:02:47.650
to hold back a president who's trying

00:02:47.650 --> 00:02:49.480
to act too quickly and do too much.

00:02:49.480 --> 00:02:53.080
- Let's go on this notion
of making war as an example.

00:02:53.080 --> 00:02:55.610
There's clear powers that Congress has

00:02:55.610 --> 00:02:58.990
to approve a war, has
the power of the purse,

00:02:58.990 --> 00:03:00.410
So, how did this happen?

00:03:00.410 --> 00:03:02.490
They just do that as a ritual now?

00:03:02.490 --> 00:03:05.030
- Well, basically there are times

00:03:05.030 --> 00:03:06.870
and Congress tries and makes attempts

00:03:06.870 --> 00:03:08.740
to try to pull power
back from the president.

00:03:08.740 --> 00:03:10.240
The only times they've been successful

00:03:10.240 --> 00:03:13.750
after the Second World War
is really after Watergate.

00:03:13.750 --> 00:03:16.230
The view was that the president
had gotten too powerful.

00:03:16.230 --> 00:03:19.030
That President Nixon, who left the office,

00:03:19.030 --> 00:03:21.060
had abused the office
and so Congress tried

00:03:21.060 --> 00:03:23.510
to pull some power back, but again,

00:03:23.510 --> 00:03:27.530
political parties which are now
very close to the president.

00:03:27.530 --> 00:03:29.940
It used to be that political
parties were not so powerful.

00:03:29.940 --> 00:03:32.410
If I'm a Republican in Congress

00:03:32.410 --> 00:03:35.160
and I want my Republican
president to do well,

00:03:35.160 --> 00:03:36.870
I'm gonna give him the power he wants

00:03:36.870 --> 00:03:38.210
because we're connected.

00:03:38.210 --> 00:03:40.560
In the old days, if the
president in the office

00:03:40.560 --> 00:03:42.650
was my party, well that's nice,

00:03:42.650 --> 00:03:44.960
but I've got my own views
and I'm in Congress,

00:03:44.960 --> 00:03:46.450
and I'm gonna do what I want.

00:03:46.450 --> 00:03:48.120
And so, essentially a lot of these powers

00:03:48.120 --> 00:03:49.690
that have gone to the president

00:03:49.690 --> 00:03:52.660
have been handed over to
him, not with a ceremony,

00:03:52.660 --> 00:03:56.860
but just by a lack of a
fight by members of Congress,

00:03:56.860 --> 00:03:59.020
in withdrawing from their traditional role

00:03:59.020 --> 00:04:01.570
as the founders wanted it as the key actor

00:04:01.570 --> 00:04:02.860
in American government.

00:04:02.860 --> 00:04:05.030
That's no longer case, in America today,

00:04:05.030 --> 00:04:06.710
the president is the key actor.

00:04:06.710 --> 00:04:08.270
- And then every time that happens

00:04:08.270 --> 00:04:10.870
the next president or the
next several presidents,

00:04:10.870 --> 00:04:13.550
we allowed that to happen to that person.

00:04:13.550 --> 00:04:14.383
I should have that power as well.

00:04:14.383 --> 00:04:15.620
- That's exactly right.

00:04:15.620 --> 00:04:17.630
It's almost like the powers conveyed

00:04:17.630 --> 00:04:19.930
to the new president like the
furniture in the Oval Office.

00:04:19.930 --> 00:04:21.813
And so, they think, well this
chair's pretty comfortable.

00:04:21.813 --> 00:04:22.646
(Sal laughs)

00:04:22.646 --> 00:04:24.070
I'm not gonna get rid of that and sit

00:04:24.070 --> 00:04:28.010
in the old uncomfortable wooden chair.

00:04:28.010 --> 00:04:30.210
I want all the plush trappings.

00:04:30.210 --> 00:04:31.450
And here's another reason.

00:04:31.450 --> 00:04:33.410
American politics has created a situation,

00:04:33.410 --> 00:04:35.110
and television has made
this so much worse,

00:04:35.110 --> 00:04:36.860
where people run for office promising

00:04:36.860 --> 00:04:38.290
the sun, the moon, and the stars.

00:04:38.290 --> 00:04:39.950
So, they say I can, Donald Trump,

00:04:39.950 --> 00:04:42.490
when he was running
said I alone can fix it.

00:04:42.490 --> 00:04:45.040
That is not the way the
country was originally founded.

00:04:45.040 --> 00:04:47.610
That one person could fix or unfix things.

00:04:47.610 --> 00:04:49.360
It was supposed to be a country

00:04:49.360 --> 00:04:51.270
with representatives
of the entire country.

00:04:51.270 --> 00:04:53.040
But, politics has created a system

00:04:53.040 --> 00:04:55.610
where, whether it's a
Republican or Democrat,

00:04:55.610 --> 00:04:57.220
they run by saying I can do anything.

00:04:57.220 --> 00:04:58.610
Well, that means when
you get in the office

00:04:58.610 --> 00:05:00.500
you want those quick powers that allow

00:05:00.500 --> 00:05:02.480
you to keep those campaign promises,

00:05:02.480 --> 00:05:05.020
and those quick powers are only quick

00:05:05.020 --> 00:05:07.470
if Congress and the
courts aren't in the way.

00:05:07.470 --> 00:05:09.210
So, politics and the way you run

00:05:09.210 --> 00:05:11.020
for office makes presidents want

00:05:11.020 --> 00:05:13.523
to have every possible
power at their disposal.


Why study US history, government, and civics?

WEBVTT
Kind: captions
Language: en

00:00:00.320 --> 00:00:03.540
- So John, if I'm a student
studying American history

00:00:03.540 --> 00:00:07.290
or U.S. government, why should I care?

00:00:07.290 --> 00:00:09.320
- Well first, there are great stories.

00:00:09.320 --> 00:00:11.790
The characters in American
history, all the way through,

00:00:11.790 --> 00:00:13.723
are fascinating, just, human beings.

00:00:13.723 --> 00:00:16.570
They would make great
movie characters, period:

00:00:16.570 --> 00:00:20.500
heroes, villains, people
who rise to courage

00:00:20.500 --> 00:00:22.950
when they were otherwise
pretty boring people.

00:00:22.950 --> 00:00:24.190
Look at Abraham Lincoln, for example.

00:00:24.190 --> 00:00:26.920
He failed miserably repeatedly,
repeatedly, repeatedly.

00:00:26.920 --> 00:00:29.140
Then he becomes the greatest President.

00:00:29.140 --> 00:00:31.540
And when he's almost at the end of his,

00:00:31.540 --> 00:00:33.030
well, he doesn't know
it's the end of his life,

00:00:33.030 --> 00:00:35.080
but later in life, after
he's had his greatness,

00:00:35.080 --> 00:00:38.660
he says, "I confess that I
was like a cork in a stream."

00:00:38.660 --> 00:00:40.507
Well, if you're a regular
person and you think,

00:00:40.507 --> 00:00:42.840
"My life feels kinda without a purpose,"

00:00:42.840 --> 00:00:45.360
you can think, well, the
greatest President in America

00:00:45.360 --> 00:00:48.880
felt like his life was
kind of bouncing around.

00:00:48.880 --> 00:00:50.970
And so, that is an
incredibly human connection

00:00:50.970 --> 00:00:53.160
to greatness, and we all need connections

00:00:53.160 --> 00:00:55.860
to greatness of whatever
kind to inspire us.

00:00:55.860 --> 00:00:58.350
Because the questions
today that America faces

00:00:58.350 --> 00:01:00.360
about freedom and
liberty and what it means

00:01:00.360 --> 00:01:02.440
to be an American, and how the power

00:01:02.440 --> 00:01:04.550
is distributed throughout our governments

00:01:04.550 --> 00:01:06.600
and our lives that affect us today

00:01:06.600 --> 00:01:08.900
were discussed and talked
about and wrestled over

00:01:08.900 --> 00:01:10.550
all throughout American history.

00:01:10.550 --> 00:01:12.570
And it is a continuing experiment.

00:01:12.570 --> 00:01:13.740
And when Thomas Jefferson wrote

00:01:13.740 --> 00:01:16.047
the Declaration of Independence, he said,

00:01:16.047 --> 00:01:18.087
"This new country that we're creating

00:01:18.087 --> 00:01:21.487
"has to constantly refresh,
each new generation

00:01:21.487 --> 00:01:23.007
"has to refresh their contact

00:01:23.007 --> 00:01:25.727
"with the original ideals that
the country was founded on.

00:01:25.727 --> 00:01:27.620
"Otherwise, the country will fail."

00:01:27.620 --> 00:01:29.510
And so, it's not only important to know

00:01:29.510 --> 00:01:31.370
what's going on around
us by studying history,

00:01:31.370 --> 00:01:33.560
but it is, according to Thomas Jefferson,

00:01:33.560 --> 00:01:37.120
your duty to stay engaged
with the ideas of America

00:01:37.120 --> 00:01:38.856
so that those ideas don't get lost

00:01:38.856 --> 00:01:42.453
in the kind of flurry and
craziness of a current moment.


Sal Khan & John Dickerson: introduction

WEBVTT
Kind: captions
Language: en

00:00:00.450 --> 00:00:02.240
- So Sal here from Khan Academy,

00:00:02.240 --> 00:00:04.410
and I'm excited to be
here with John Dickerson,

00:00:04.410 --> 00:00:06.480
co-host of CBS This Morning.

00:00:06.480 --> 00:00:07.720
- And I'm excited to be here too.

00:00:07.720 --> 00:00:08.760
(Sal laughing)

00:00:08.760 --> 00:00:09.860
- And some of you all might be wondering,

00:00:09.860 --> 00:00:11.260
what are we doing together?

00:00:11.260 --> 00:00:14.610
And we are going to be
talking about civics

00:00:14.610 --> 00:00:16.490
and government and American history.

00:00:16.490 --> 00:00:18.180
And you're gonna see a series of videos

00:00:18.180 --> 00:00:22.350
on Kahn Academy tapping
into John's expertise.

00:00:22.350 --> 00:00:24.680
- You know, when I cover
the news every single day,

00:00:24.680 --> 00:00:26.350
one of the first things I do is I go back

00:00:26.350 --> 00:00:28.920
and look at our amazing American
history for two reasons.

00:00:28.920 --> 00:00:30.690
One, what has the
standard been in the past?

00:00:30.690 --> 00:00:32.030
How have people behaved in the past?

00:00:32.030 --> 00:00:33.870
So we know whether what's
happening now is new,

00:00:33.870 --> 00:00:36.910
crazy, interesting, in keeping
with the American experience.

00:00:36.910 --> 00:00:39.050
And the other thing is when
you learn about history,

00:00:39.050 --> 00:00:40.970
when you look to the past,
you can sometimes have a clue

00:00:40.970 --> 00:00:42.810
about what's gonna happen in the future.

00:00:42.810 --> 00:00:44.737
Even though things are much
different now with technology

00:00:44.737 --> 00:00:46.830
and the pace of things,

00:00:46.830 --> 00:00:48.920
turns out, human beings
behave the same way

00:00:48.920 --> 00:00:51.460
in a lot of ways all
throughout American history.

00:00:51.460 --> 00:00:53.450
- So this is gonna be a very exciting,

00:00:53.450 --> 00:00:55.660
as you could tell, series of videos

00:00:55.660 --> 00:00:57.690
that some of 'em are
gonna be John and myself.

00:00:57.690 --> 00:00:59.450
And some of 'em are gonna be John,

00:00:59.450 --> 00:01:02.110
giving us kind of connecting
what you learn in school

00:01:02.110 --> 00:01:04.260
to what's happening in
the world around us.


Interpreting change in speed from velocity-time graph

WEBVTT
Kind: captions
Language: en

00:00:00.310 --> 00:00:02.600
- [Instructor] An object
is moving along a line.

00:00:02.600 --> 00:00:06.910
The following graph gives the
object's velocity over time.

00:00:06.910 --> 00:00:08.450
For each point on the graph,

00:00:08.450 --> 00:00:12.260
is the object speeding up,
slowing down, or neither?

00:00:12.260 --> 00:00:15.270
So, pause this video and see
if you can figure that out.

00:00:15.270 --> 00:00:16.970
All right, now, let's do it together,

00:00:16.970 --> 00:00:18.310
and first, we need to make sure

00:00:18.310 --> 00:00:19.370
we're reading this carefully,

00:00:19.370 --> 00:00:20.203
'cause they're not asking

00:00:20.203 --> 00:00:21.970
is the velocity increasing,

00:00:21.970 --> 00:00:22.900
decreasing, or neither,

00:00:22.900 --> 00:00:25.780
they're saying is the object speeding up,

00:00:25.780 --> 00:00:27.780
slowing down, or neither?

00:00:27.780 --> 00:00:29.810
So, they're talking about speed,

00:00:29.810 --> 00:00:32.420
which is the magnitude of velocity.

00:00:32.420 --> 00:00:34.990
You can think of it as the
absolute value of velocity,

00:00:34.990 --> 00:00:35.823
especially when we're thinking

00:00:35.823 --> 00:00:38.210
about it in one dimension, here.

00:00:38.210 --> 00:00:39.910
So, even though they're
not asking about velocity,

00:00:39.910 --> 00:00:41.350
I'm going to actually wanna answer both

00:00:41.350 --> 00:00:42.730
so that we can see how sometimes,

00:00:42.730 --> 00:00:44.230
they move together, velocity and speed,

00:00:44.230 --> 00:00:47.010
but sometimes, one might be increasing

00:00:47.010 --> 00:00:49.120
while the other might be decreasing.

00:00:49.120 --> 00:00:51.270
So, if we look at this
point right over here,

00:00:51.270 --> 00:00:53.560
where our velocity is
two meters per second,

00:00:53.560 --> 00:00:55.920
the speed is the absolute
value of the velocity,

00:00:55.920 --> 00:00:57.670
which would also be two meters per second,

00:00:57.670 --> 00:00:59.440
and we can see that the slope

00:00:59.440 --> 00:01:02.120
of the velocity-time graph is positive,

00:01:02.120 --> 00:01:05.210
and so, our velocity is increasing

00:01:05.210 --> 00:01:07.550
and the absolute value of our velocity,

00:01:07.550 --> 00:01:10.170
which is speed, is also increasing.

00:01:10.170 --> 00:01:14.070
A moment later, our velocity
might be 2.1 meters per second

00:01:14.070 --> 00:01:16.920
and our speed would also
be 2.1 meters per second.

00:01:16.920 --> 00:01:18.750
That seems intuitive enough.

00:01:18.750 --> 00:01:19.900
Now, we get the other scenario

00:01:19.900 --> 00:01:21.640
if we go to this point right over here.

00:01:21.640 --> 00:01:23.510
Our velocity is still positive,

00:01:23.510 --> 00:01:25.450
but we see that our velocity-time graph

00:01:25.450 --> 00:01:27.940
is now downward sloping, so,

00:01:27.940 --> 00:01:31.840
our velocity is decreasing
because of that downward slope,

00:01:31.840 --> 00:01:35.780
and the absolute of our
velocity is also decreasing.

00:01:35.780 --> 00:01:39.200
Right at that moment, our
speed is two meters per second,

00:01:39.200 --> 00:01:43.440
and then, a moment later, it
might be 1.9 meters per second.

00:01:43.440 --> 00:01:45.440
All right, now, let's go to this point.

00:01:45.440 --> 00:01:47.970
So, this point is really interesting.

00:01:47.970 --> 00:01:50.200
Here, we see that our velocity,

00:01:50.200 --> 00:01:54.030
the slope of the tangent
line, is still negative,

00:01:54.030 --> 00:01:56.670
so, our velocity is still decreasing.

00:01:56.670 --> 00:01:58.080
What about the absolute value

00:01:58.080 --> 00:02:00.180
of our velocity, which is speed?

00:02:00.180 --> 00:02:02.550
Well, if you think about
it, a moment before this,

00:02:02.550 --> 00:02:05.490
we were slowing down to
get to a zero velocity,

00:02:05.490 --> 00:02:08.250
and a moment after this,
we're going to be speeding up

00:02:08.250 --> 00:02:10.080
to start having negative velocity.

00:02:10.080 --> 00:02:12.180
You might say, wait, speeding
up for negative velocity?

00:02:12.180 --> 00:02:14.090
Remember, speed is the absolute value,

00:02:14.090 --> 00:02:16.980
so, if your velocity goes from zero

00:02:16.980 --> 00:02:19.350
to negative one meters per second,

00:02:19.350 --> 00:02:22.490
your speed just went from
zero to one meter per second,

00:02:22.490 --> 00:02:24.620
so, we're slowing down here
and we're speeding up here,

00:02:24.620 --> 00:02:27.560
but right at this moment,
neither is happening.

00:02:27.560 --> 00:02:30.890
We are neither speeding
up nor slowing down.

00:02:30.890 --> 00:02:32.820
Now, what about this point?

00:02:32.820 --> 00:02:36.550
Here, the slope of our
velocity-time graph,

00:02:36.550 --> 00:02:39.050
or the slope of the tangent
line, is still negative,

00:02:39.050 --> 00:02:43.100
so, our velocity is still
decreasing, but what about speed?

00:02:43.100 --> 00:02:45.430
Well, our velocity is already negative,

00:02:45.430 --> 00:02:47.480
and it's becoming more negative,

00:02:47.480 --> 00:02:49.120
so, the absolute value of velocity,

00:02:49.120 --> 00:02:50.610
which is two meters per second,

00:02:50.610 --> 00:02:53.010
that is increasing at that moment in time,

00:02:53.010 --> 00:02:54.680
so, our speed is actually increasing,

00:02:54.680 --> 00:02:57.320
so, as you notice here,
you see a difference.

00:02:57.320 --> 00:02:59.010
Now, what about this point?

00:02:59.010 --> 00:03:01.230
Well, the slope of the tangent line here

00:03:01.230 --> 00:03:04.790
of our velocity-time graph
is zero right at that point,

00:03:04.790 --> 00:03:07.410
so, that means that our
velocity is not changing,

00:03:07.410 --> 00:03:10.803
so, you could say velocity not changing,

00:03:11.920 --> 00:03:13.970
and if speed is the absolute value

00:03:13.970 --> 00:03:15.500
or the magnitude of velocity, well,

00:03:15.500 --> 00:03:19.300
that will also be not changing,
so, we would say speed is,

00:03:19.300 --> 00:03:23.100
I'll say, neither slowing
down nor speeding up.

00:03:23.100 --> 00:03:25.810
Last but not least, this
point right over here.

00:03:25.810 --> 00:03:28.300
The slope of the tangent line is positive,

00:03:28.300 --> 00:03:32.320
so, our velocity is increasing,
but what about speed?

00:03:32.320 --> 00:03:35.900
Well, the speed here is
two meters per second.

00:03:35.900 --> 00:03:38.220
Remember, it'd be the absolute
value of the velocity,

00:03:38.220 --> 00:03:41.410
and the absolute value
is actually going down

00:03:41.410 --> 00:03:43.870
if we forward in time a little bit,

00:03:43.870 --> 00:03:46.300
so, our speed is actually decreasing.

00:03:46.300 --> 00:03:49.060
We are slowing down as our velocity

00:03:49.060 --> 00:03:50.400
gets closer and closer to zero,

00:03:50.400 --> 00:03:51.960
'cause the absolute value

00:03:51.960 --> 00:03:55.383
is getting closer and closer to zero.


Developing an American identity, 1800-1848

WEBVTT
Kind: captions
Language: en

00:00:00.220 --> 00:00:02.390
- [Instructor] In this video
I want to take a look back

00:00:02.390 --> 00:00:06.130
at the period from 1800 to 1848,

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kinda from a bird's eye view.

00:00:08.700 --> 00:00:11.510
This is a huge time in American history.

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In 1800, the United States
was just a fledgling nation,

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less than 20 years out from
winning its independence.

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Political parties were in their infancy,

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infrastructure was
practically non-existent,

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and one disastrous war with a world power,

00:00:26.880 --> 00:00:29.160
with the likes of Great Britain or France,

00:00:29.160 --> 00:00:31.150
could easily have wiped it out.

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But fast forward to 1848,
less than 50 years later,

00:00:34.980 --> 00:00:37.100
and by then the United
States had developed

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a great deal as a unified
independent nation.

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It occupied a vast amount of
territory in North America,

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trains and steamships transported
goods to distant markets,

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factories churned out textiles,

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and politics saw the rise and fall

00:00:53.440 --> 00:00:56.860
of not one, but two party systems.

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Despite all this growth,
in 1848 the United States

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was just 12 years away from the onset

00:01:03.210 --> 00:01:06.510
of an incredibly bloody
civil war that pitted

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Southern states against
the U.S. government.

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This seems like quite a contradiction.

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Over the course of the first
half of the 19th century,

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was the United States developing

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a unified national identity?

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Or were its geographic sections

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developing a divided regional identity,

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barely held together by the Constitution?

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What we're doing here really

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is asking a historical question.

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If you saw this on the AP exam,

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the question might look
something like this.

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Explain the extent to
which politics, economics,

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and foreign policy
promoted the development

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of the American identity
from 1800 to 1848.

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Sounds pretty fancy schmancy.

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But we can translate that
to a simpler question.

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What tied the United States
together as a country

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over the course of 1800 to
1848, and what split it apart?

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To answer this, let's review what

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happened in this period
in these three areas,

00:02:04.180 --> 00:02:07.950
politics, economics, and foreign policy,

00:02:07.950 --> 00:02:09.930
and see if we think they contributed

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to a unified American identity

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or a divided regional identity.

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And just to remind you
this is a big overview

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of the historical developments
from 1800 to 1848.

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I'm not gonna take a lot of time here

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to explain everything in depth,

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but if you find that you're unfamiliar

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with some of the things we discuss,

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make a note of it and then go back

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to review that concept
when you've got some time.

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Okay, as we set about
to answer this question,

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let's just brainstorm some of
the major political, economic,

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and foreign policy developments
in this time period.

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It doesn't have to be an exhaustive

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list of everything that happened,
just some key highlights.

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I'll suggest a few, but
feel free to pause the video

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and see what you can think of on your own.

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Alright, what happened in politics?

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Well, there was the development
of political parties.

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First, the Federalists and
the Democratic Republicans,

00:03:02.760 --> 00:03:04.310
and then later on they were replaced

00:03:04.310 --> 00:03:07.130
with the Jacksonian
Democrats and the Whigs.

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There was the expansion
of the right to vote

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to almost all white men in this era,

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and there were a lot of
political controversies.

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Two that come to mind are
the Missouri Compromise

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and the Nullification Crisis.

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So which of these things
contributed to a unified identity,

00:03:24.740 --> 00:03:28.000
and which contributed
to a regional identity?

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Well, I would say that
the Missouri Compromise

00:03:30.100 --> 00:03:33.340
and the Nullification
Crisis were both examples

00:03:33.340 --> 00:03:37.080
of regional identity
trumping American identity,

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since they concerned the balance of power

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between free states and slave states,

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and whether states or
the Federal Government

00:03:44.300 --> 00:03:46.030
should have the final say.

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The expansion of the right to vote

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seems like a point for unification to me

00:03:52.030 --> 00:03:54.640
since it celebrated American democracy

00:03:54.640 --> 00:03:58.190
as the birthright of
white men from all states.

00:03:58.190 --> 00:04:02.290
On political parties, I might
say this is inconclusive.

00:04:02.290 --> 00:04:06.190
There are elements of both
unity and division among them

00:04:06.190 --> 00:04:08.750
since political parties
weren't exclusively defined

00:04:08.750 --> 00:04:10.710
by region in this time period,

00:04:10.710 --> 00:04:13.130
but they were often defined by how

00:04:13.130 --> 00:04:15.480
much power they believed
the Federal Government

00:04:15.480 --> 00:04:18.410
should have compared to the states.

00:04:18.410 --> 00:04:20.880
Okay, on to economics.

00:04:20.880 --> 00:04:23.910
Major developments in
this time period include

00:04:23.910 --> 00:04:28.840
the Market Revolution, the
controversy over tariffs,

00:04:28.840 --> 00:04:33.190
and the increasing separation
between the economies

00:04:33.190 --> 00:04:37.210
of the industrial North
and the agricultural South.

00:04:37.210 --> 00:04:41.270
Of these, I would say that
separate economic systems

00:04:41.270 --> 00:04:44.780
definitely promoted a
divided regional identity.

00:04:44.780 --> 00:04:48.690
The controversy over tariffs
also promoted divisions

00:04:48.690 --> 00:04:50.700
in that Southern plantation owners

00:04:50.700 --> 00:04:53.620
thought that tariffs gave advantage

00:04:53.620 --> 00:04:56.580
to Northern manufacturers
at their expense.

00:04:56.580 --> 00:04:59.950
The Market Revolution is a
bit tricky to categorize.

00:04:59.950 --> 00:05:02.350
It promoted some ties between the sections

00:05:02.350 --> 00:05:05.870
because it became easier
to conduct business over

00:05:05.870 --> 00:05:08.220
long distances due to innovations

00:05:08.220 --> 00:05:10.700
in transportation and communication.

00:05:10.700 --> 00:05:13.100
But a lot of the major networks

00:05:13.100 --> 00:05:17.460
of transportation and
communication connected the North

00:05:17.460 --> 00:05:21.300
and the West to each other, not the South.

00:05:21.300 --> 00:05:23.300
Lastly, foreign policy.

00:05:23.300 --> 00:05:26.560
In this era there was the War of 1812,

00:05:26.560 --> 00:05:30.100
as well as westward expansion
that caused conflict

00:05:30.100 --> 00:05:33.380
with Native Americans and with Mexico.

00:05:33.380 --> 00:05:35.910
I'd say that the War of
1812 was a force that

00:05:35.910 --> 00:05:39.680
brought Americans together in
a shared sense of patriotism

00:05:39.680 --> 00:05:42.510
following victories like
the Battle of New Orleans.

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The westward expansion was
a bit more of a mixed bag.

00:05:45.960 --> 00:05:49.190
In general, most white Americans supported

00:05:49.190 --> 00:05:51.220
the concept of Manifest Destiny

00:05:51.220 --> 00:05:53.550
and thought that the
removal of Native Americans

00:05:53.550 --> 00:05:55.400
for that purpose was justified.

00:05:55.400 --> 00:05:58.910
But westward expansion also
led to regional conflict

00:05:58.910 --> 00:06:01.900
because the admission of
new states into the Union

00:06:01.900 --> 00:06:04.070
threatened the balance of power between

00:06:04.070 --> 00:06:06.300
free and slave states in Congress.

00:06:06.300 --> 00:06:09.400
So based on the evidence
we've gathered here,

00:06:09.400 --> 00:06:11.480
let's see if we can formulate a

00:06:11.480 --> 00:06:14.110
thesis statement to answer this question.

00:06:14.110 --> 00:06:18.390
The prompt is asking us
to evaluate the extent

00:06:18.390 --> 00:06:20.620
to which developments in politics,

00:06:20.620 --> 00:06:22.890
economics, and foreign policy promoted

00:06:22.890 --> 00:06:24.830
the development of an American identity.

00:06:24.830 --> 00:06:27.400
So I think that we want
to approach this not as

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an either-or, or a yes-no question,

00:06:30.410 --> 00:06:33.100
but rather a question of degree.

00:06:33.100 --> 00:06:35.320
I would say that the overall evidence

00:06:35.320 --> 00:06:38.710
here points to a divided regional

00:06:38.710 --> 00:06:41.290
identity with a few points of unity.

00:06:41.290 --> 00:06:45.040
Americans agreed that the
United States needed to expand,

00:06:45.040 --> 00:06:48.510
and that democracy was the
birthright of all white men,

00:06:48.510 --> 00:06:51.520
but in almost every
other aspect of politics,

00:06:51.520 --> 00:06:53.640
economics, and foreign policy they were

00:06:53.640 --> 00:06:56.020
divided along sectional lines.

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Would you come to the same conclusion?

00:06:58.150 --> 00:07:01.490
Remember this is only one way
of answering this question.

00:07:01.490 --> 00:07:04.000
You may have come up with
some different examples,

00:07:04.000 --> 00:07:05.850
or you might interpret these examples

00:07:05.850 --> 00:07:08.210
in a different way than
I have, and that's okay.

00:07:08.210 --> 00:07:12.010
The next step now that you've
evaluated your evidence

00:07:12.010 --> 00:07:13.990
and composed your thesis statement,

00:07:13.990 --> 00:07:16.710
is to think about how you
might arrange the thoughts

00:07:16.710 --> 00:07:19.953
you've gathered here into
an argumentative essay.