Think of a large mass moving at a high speed v colliding with a small mass that starts out not moving. This could be that bowling ball hitting the ping-pong ball, or a table tennis paddle hitting the ball. For all of those, the player holding the paddle, racquet etc, effectively adds to its mass: the surface of the paddle doesn't slow down much of impact. If the (much less massive) ball is not moving at the impact, how does it speed compare to the speed of the large mass hitting it? In other words, if the racquet is moving at speed v when it hits the ball, about how fast would you expect the ball to be moving after the hit? does that seam plausible