Springaling... should be easy?

Question

A spring has a force constant of 4000 n/m. The spring is initially streched by 2 CM beyond its equilibrium config. Then the spring is compressed until its length is 6 cm less than the relaxed length. What is the net ammount of work done by the spring AND the person moving the spring?

Answer 1

In each case, the change in spring energy is 1/2 k x ^2 where x is displacement from equilibrium. The change in energy is equal to the work done on the spring.