1. A 30 cm spring is compressed to 2 cm. a force of 200 N was used to do this. How much potential energy is stored in the spring?

2. A 5 kg mass is suspended from a spring. The spring develops 100 J of potential energy. What is the spring constant of the spring?

3. A ball is at rest on top of a 15 meter high hill. It rolls down the hill and is stopped by compressing a spring. If the spring is compressed 56 cm, find the spring constant.

4. A 7 kg rock is placed on a spring that has been compressed 48 cm. The spring is released and the rock flies straight upward. As soon as the rock leaves the spring its velocity is 50 m/s. What is the spring constant for the spring?

5. A spring has been stretched 16 cm. The force pulling the spring is reduced so that the stretched length is only 4 cm. By what factor has the potential energy in the spring been reduced?

6. 600N is used to compress a spring to half its initial resting length. How much will the spring be compressed if 800N is used to compress it?

7. 40N stretches a spring from 15 cm to 38 cm. What is the spring constant of the spring?