# Workdone on a spring

1. Oct 7, 2007

### kring_c14

1. The problem statement, all variables and given/known data

to stretch a spring 3 cm from its unstretched lenght, 12 J of work must be done. How much work must be done to compress this spring 4 cm from its unstretched lenght?

2. Relevant equations

W=1/2 kx$$^{2}$$

3. The attempt at a solution

a. W=1/2 kx$$^{2}$$

k=24/.03
k=800N/m

b. W=1/2 kx$$^{2}$$
W= 1/2 (800)(-0.04)$$^{2}$$
w= 0.64J

im not sure if this is correct..

2. Oct 7, 2007

### kring_c14

we haven't discuss this in class yet, so im not sure if im doing it right

Last edited: Oct 7, 2007
3. Oct 7, 2007

### atavistic

Its x square...you have used x.Rest seems fine.