posted by harkaran .
10 people,each of mass 70 kg, stand on a boat with a mass of 1000 kg. they jump off one end of the boat with velocity 1 m/s relative to the boat. the boat rolls in the opposite direction without friction.
a what is the final velocity of the boat if all the people jump at the same time?
b. what is the final velocity of the boat if the people jump off one at a time?
I don't get it. Why should the boat roll? In what direction are the people jumping?