# Homework Help: Conceptual Question on the Force of a relaxed spring

1. Sep 10, 2010

### Kibbel

1. The problem statement, all variables and given/known data
When running a moving cart into a relaxed spring, will the force of the spring be constant on the cart?

2. Relevant equations
$$\Delta$$P$$\rightarrow$$ =$$\rightarrow$$Fnet$$\Delta$$t

or F = 1/2kx^2?

3. The attempt at a solution

my guess is that the more you compress or strech a spring, the stronger the opposing force

2. Sep 10, 2010

### G01

Your conceptual explanation is correct. That is essentially Hooke's Law. The force caused by an ideal spring increases linearly with it's compression (or expansion).

However, F does not equal 1/2kx^2. That is the potential energy. F=-kx