Question

In each of three experiments, puck A (of mass m) is launched on a frictionless surface with speed v_0 toward stationary pucks X, Y, and Z. Pucks X, Y, Z all have the same mass M, which is greater than the mass of puck A(M > m). X, Y, Z are made of the different materials. The collisions are not necessarily elastic. In Exp. 1, puck A hits puck X and stops. In Exp. 2, puck A rebounds to the left with speed 1/2 v_0. In Exp. 3, puck A continues to the right with speed 1/6 v_0. In Exp. 2, is the magnitude of the change in momentum of puck A greater than, less than, or or equal to the magnitude of the change in momentum of puck Y ?Explain. In Exp. 2, is the magnitude of the final momentum of puck Y (p_yf) greater than, less than, or equal to the magnitude of the initial momentum of puck A (p_AL)? Explain. Rank the final speeds of pucks X, Y, and Z from greatest to smallest. Explain For each of the outcomes is permitted or forbidden by the principle of momentum conservation. Explain in each case. The final speed of puck Y is v_0 (the initial speed of puck A). The final speed of puck Z is v_0.

Answer 1

In experiment 2 :

since momentum is conserved in any kind of collision

hence change in momentum of puck A = Change in momentum of puck Y

In experiment 2 :

final momentum of puck Y > initial momentum of puck A

since final momentum of puck A is in opposite direction