Elastic potential energy is equal to the force times the distance of movement. Elastic potential energy = force x distance of displacement. Because the force is = spring constant x displacement, then the Elastic potential energy = spring constant x displacement squared.
We would need to know how long it took to do the work.
Power = (work) / (time).
Physical change :) Hope you get it right! :D Good luck! let me know what else I can help you with. Have a great day! :D
4. 1 and 2 only.
1. the downward force is the force of gravity.
<span>2. The upward force exerted is the Normal reaction from the floor.</span>