# Homework Help: Total elastic potential energy of a compressed spring?

1. Jan 17, 2012

### ErwinJL

1. The problem statement, all variables and given/known data
A spring with a spring constant of 4 newtons per meter is compressed by a force of 1.2 newtons. What is the total elastic potential energy stored in this compressed spring?

k = 4 N/m
F = 1.2 N
PE = ?

2. Relevant equations
PE = (1/2)(k)(x)^2

3. The attempt at a solution
Using the information from the problem, I can use PE = (1/2)(k)(x)^2 to find the stored potential energy. I can plug in 4 N/m for k, but I am stuck with plugging in the distance compressed for x. The problem gives me the amount of force used to compress the spring, but I don't know how to find the distance compressed using it.

2. Jan 17, 2012

### Curious3141

Are you familiar with Hooke's Law?

3. Jan 17, 2012

### ErwinJL

Yes, today I asked my teacher about it in class, and he explained it to me. We know the spring constant is 4 N/m and the force applied, which is 1.2 newtons. Both are incorporated in Hooke's law(F = -kx); using it, we can solve for x by dividing the force by the spring constant, leaving .3 meters for distance compressed. Then we can use that with what we already know to find stored potential energy .

Thanks for the help anways