A boy throws a ball to another boy who throws it back with half the original speed. What is the ratio of the final kinetic energy to the initial kinetic energy of the ball?
A) 0.25
B) 0.50
C) 2.00
D) 0.75
E) 1.0

Question

Quizplus · Accepted Answer

The kinetic energy of an object is proportional to the square of its speed. If the speed is halved, the kinetic energy becomes (1/2)^2 = 1/4 of the original kinetic energy. Thus, the ratio of the final kinetic energy to the initial kinetic energy is 0.25.

A Boy Throws a Ball to Another Boy Who Throws