A billiard ball collides in an elastic head-on collision with a second identical ball.What is the kinetic energy of the system after the collision compared to that before collision?
A)the same as
B)one fourth
C)twice
D)four times

Question

Quizplus · Accepted Answer

In an elastic collision, the total kinetic energy of the system is conserved. Since the two balls have identical mass and collide head-on, they will experience an equal and opposite change in velocity, and therefore their kinetic energies will be equal to each other before and after the collision. Therefore, the kinetic energy of the system before and after the collision will be the same.

A Billiard Ball Collides in an Elastic Head-On Collision with a Second