Elastic collision
A collision where energy is conserved.
Definition 5.8 (Elastic Collision)
An elastic collision is a collision where energy is conserved.
Reflection from a massive wall
A ball of mass bounces off the Earth or a wall of mass , with incoming and outgoing -momenta and , and the momentum of the Earth or wall after the collision. By conservation of total momentum,
By conservation of energy,
Substituting the first equation into the second gives
If , then , so
Hence the angle of reflection equals the angle of incidence: .
Impulse
The change in momentum over a short time is called an impulse .
Related
Stated in
- Definition 5.8 (Elastic Collision)§5.6 Normal Forces