To catch the ball and then throw it back again at the same speed requires twice as much impulse. On a skateboard, you'd recoil and gain momentum when throwing the ball, you'd also gain the same momentum by catching the ball, and you'd gain twice the momentum if you did both-catch and then throw the ball at its initial speed in the opposite direction. The impulse will be greater if the hand is made to bounce, because there is a greater change in the momentum of hand and arm, accompanied by a greater impulse. The force exerted on the bricks is equal and opposite to the force of the bricks on the hand. Fortunately, the hand is resilient and toughened by long practice.
Impulse is greater for reflection, which is in effect, bouncing.
The vanes therefore recoil more from the silvered sides. The vanes in the sketch therefore rotate clockwise as viewed from above. The black surface absorbs radiation and is heated, which warms the nearby air. This is like the freight cars of equal mass shown in Figure 5.11. The chunks have equal and opposite momenta, since their total momentum must be zero.