Friday January 11th notes

Elastic potential energy-when work is done in compressing/stretching a spring, elastic potential energy is stored in the spring. 

Hookes law- force of the spring=(constant)(x)

Elastic potential energy- PEs=(1/2)kx*2

practice problem:

How much force is needed to stretch the spring .8m using a constant of .6N/m

Fs=kx

Fs=(.6N/m)(.8m)

Fs=.48N

How much work is done on the spring?

W=Et=changePE+changeKE+changeQ

W=changePE

W=(1/2)kx*2

W=(1/2)(.6N/m)(.8m)*2

W=.192J

Doing work on a spring changes its potential energy