posted by Zach .
Batman (mass = 90 kg) jumps straight down from a bridge into a boat (mass = 530 kg) in which a criminal is fleeing. The velocity of the boat is initially +20 m/s. What is the velocity of the boat after Batman lands in it?
The total momentum for motion along the water does not change, assuming the water applies negligible retarding friction along that direction as the boat stabilizes. Therefore
M * 20 = (M + m)V
V = M*20/(M+m)
= (530/620)*20 m/s = ?