Consider that two bullets of unequal masses have been fired with equal velocity toward a wooden block resting on a frictionless surface and not constrained against anything. One bullet is made of rubber and bounces off of the block (assume its velocity is zero after hitting the block), while the second bullet is made of steel and embeds in the block upon impact. In which case does the block have the larger velocity following the impact? The mass of the rubber bullet is half of the block, while that of the steel bullet is the same as that of the block.