In a totally elastic collision of two billiard balls (2-dimensional elastic collision),which of the following quantities is not conserved?
A)total kinetic energy
B)total momentum
C)x-component of the total momentum
D)total velocity
E)total mass

Question

Quizplus · Accepted Answer

In a totally elastic collision of two billiard balls, all quantities including total kinetic energy, total momentum (including both x and y components), and total mass are conserved. The only quantity that is not conserved is the total velocity, as the velocities of the individual balls may change direction and magnitude after the collision.

In a Totally Elastic Collision of Two Billiard Balls (2-Dimensional