Answer: Work Needed to Compress Spring 4 cm

[kring_c14]

Homework Statement

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?

Homework Equations

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

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..

 

[kring_c14]

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

 

[atavistic]

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