Question

Object A with a mass of 500 kilograms hits stationary object B with a mass of 920 kilograms. If the collision is elastic, what happens after the collision?

Answer 1

If the collision is head-on and elastic, the relative velocities of the two objects will be the same magnitude after the collision, but in opposite directions. For example if object A was moving at 10 m/s toward B then the gap is closing at 10m/s. After the collision the gap will be widening at 10 m/s, but the velocities of each must be worked out using the masses of each and the conservation of momentum. The sum of the final momenta would be in the same direction as A was initially moving P=500*v, whatever v was.