In a physics demonstration, two rubber balls are dropped down a tube towards the ground, with the lighter ball behind, and not quite in contact with, the heavier ball. The heavier ball collides with the ground and bounces, then collides with the still descending lighter ball. Assume that all the collisions are elastic. In one such demonstration, the heavier ball has a mass of 500 grams, the lighter one a mass of 100 grams, and they are released 1.00 m above the ground. How high does the lighter ball rise after the two collisions?
A) 5.44 m
B) 10.3 m
C) 2.95 m
D) 5.89 m
E) 1.00 m

Question

Quizplus · Accepted Answer

In an elastic collision, the lighter ball can gain a significant amount of kinetic energy from the heavier ball. Using conservation of momentum and energy, the lighter ball can rise to a height of approximately 5.44 m after the collisions.

In a Physics Demonstration, Two Rubber Balls Are Dropped Down