A spring is compressed 2 cm and stores 4 J of elastic potential energy. If compressed to 4 cm, approximately how much energy does it store?
A8 J
B16 J
C2 J
D4 J
Elastic PE depends on the square of the compression. Doubling the compression from 2 cm to 4 cm means 2² = 4 times the energy: 4 × 4 = 16 J.
Question 2 True / False
A stretched rubber band stores elastic potential energy.
TTrue
FFalse
Answer: True
When you stretch a rubber band from its natural shape, you do work on it, and that energy is stored as elastic potential energy until the band is released.
Question 3 Short Answer
Where does the energy come from when a compressed spring launches a ball?
Think about your answer, then reveal below.
Model answer: The energy comes from the elastic potential energy stored in the compressed spring. Work was done to compress the spring, and that stored energy converts to the ball's kinetic energy when released.
Energy is conserved. The work you did compressing the spring was stored as elastic PE, which converts to the ball's KE upon release.