In a stunt for an action movie, the 100 kg actor jumps from a train which is crossing a river bridge. On the river below, the heroine is tied to a raft floating towards a waterfall at 3 m s−1. The raft and heroine have a total mass of 200 kg.
a If the hero times his jumps perfectly so as to land on the raft, and his velocity is 12 m s−1 at an angle of 80° to the river current, what will be the velocity of the raft immediately after he lands? Draw a vector diagram to show the momentum addition. (Ignore any vertical motion.)
b If the waterfall is 100 m downstream, and the hero landed when the raft was 16 m from the bank, would they plummet over the fall? (Assume the velocity remains constant after the hero has landed.)