A basketball bouncing back to your hand when you dribble. A cue ball sending a numbered pool ball into the pocket. What physics principle are these examples of?

When a ball bounces back with the same force it had when it left your hand, or propels a ball with the same speed that it hit it with, that's elastic collision. When a billiard ball crashes into a second, identical ball and comes to a sudden stop, knocking the second ball away with almost all the momentum the first ball had originally, that's about as close as we ever get to an elastic collision.

Asked by Tom Cohen · Last updated 5 years ago · 1K views