A pair of air pucks on an air table are set in motion when a compressed spring between them is released. If one puck moves with twice the speed of the other, then its mass is
A)half the mass of the other.
B)the same mass as the other.
C)twice the mass as the other.
D)need more information

Question

Quizplus · Accepted Answer

According to the conservation of momentum, the total momentum of the system before and after the spring is released remains constant. If one puck moves with twice the speed of the other, it must have half the mass of the other so that the total momentum is conserved. Thus, the answer is A)half the mass of the other.

A Pair of Air Pucks on an Air Table Are