Solving for Work Done on Compressing Spring: What Am I Doing Wrong?

[dcgirl16]

I have this question
THe work done to compress a spring with a force constant of 290.0 N/m a total of 12.3mm is.. and the answer is .0219J but i can't get this answer
This is what i did
F=kx
F=290(.0123)
F=3.567

W=Fcos0 d
W=3.567(.0123)
.0439J

What am i doing wrong??

 

[Office_Shredder]

Notice the force is different for different distances, thus, Fd doesn't really work here.

Do you know what the potential energy is for a spring with spring constant k compressed a distance of x?

 

[dcgirl16]

do you mean the elastic potential Ee=1/2kx2
and then would i use that in the work equation?

 

[Office_Shredder]

It's conservation of energy. Work must have been done against the spring to give the spring that potential energy.