A tennis ball noticeably changes shape when it bounces on the ground. This compression is evidence of elastic energy.
Assume that the mass of the ball is 0.057 kg. The spring constant of a tennis ball is
440 N/m, meaning that it takes 440 N of force to compress the ball by 1 meter (of
course a tennis ball is much smaller than 1 meter, but the proportion 4.4 N per 1
cm also works).
How much elastic energy is stored in the tennis ball when it is compressed by 0.03
m?
Bonus: assuming no energy is transferred into vibration, heat or sound (impossible,
but let's pretend to keep it simple) what speed would the ball have when it leaves
the ground? hint: assume all Eel turns into Ek.