Spring Constant and Compression Problem

[bbreezy]

Homework Statement

The potential energy stored in the compressed spring of a dart gun, with a spring constant of 62.50 N/m, is 0.540 J. Find by how much is the spring is compressed.

Homework Equations

I know that F=-k*change in x and also spring= 1/2kx^2

The Attempt at a Solution

Using the two formulas above, i tried 1/2(62.5)(x^2) which is .540? but I am getting the wrong answer.. I also tried x=0 and canceling it. I am not sure what I am doing wrong here.

 

[PhanthomJay]

What number did you get using the 2nd equation (don't use the first)? Please show your math. And why would you try x = 0?

 

[bbreezy]

I got 9.1125... i did 1/2(62.5)(.540^2)

 

[bbreezy]

I know X is the "displacement" but I am drawing a blank as to what that number is

 

[SammyS]

Are you saying you solved (1/2)(62.6)x²=0.540 for x, and got the wrong answer?

 

[Booke]

I can tell you that the spring is not compressed 9 meters unless you have one big dart gun hehe. Looks like you have your numbers mixed up. Potential energy of a spring is equal to 1/2k*x^2 so your equation should look like this

.540=1/2k*x^2, x is how much the spring is compressed.