- Give one example of each of the following:
- Small mass but high kinetic energy
- Large mass but low kinetic energy
- Prove mathematically that the total mechanical energy of a freely falling body in air is conserved.
Answer:
- A cricket/hockey ball which has been hit hard and is travelling fast.
- A shot put thrown by an athlete
- (b) Let the body of mass m at height h above the ground starting from rest, be falling freely.
Total energy of the body at height h
mgh (PE) + 0 (KE) = mgh
After the body has fallen freely through a distance x (say),
