Throwing caution to the wind,Bob hops off a bridge onto a small boat that is travelling under the bridge at 12.0 m/s.If Bob's mass is 85.0 kg,and the boat's (with its driver)is 451 kg,how fast is the boat moving after Bob lands on it? Assume Bob falls straight down into the boat.
A)9.7 m/s
B)10.1 m/s
C)11.0 m/s
D)14.3 m/s

Question

Quizplus · Accepted Answer

Using the conservation of momentum, the initial momentum of the system (Bob and the boat) is equal to the final momentum. The initial momentum is the momentum of the boat alone (451 kg * 12.0 m/s). After Bob lands, the total mass is 536 kg (85 kg + 451 kg). Solving for the final velocity gives approximately 10.1 m/s.

Throwing Caution to the Wind,Bob Hops Off a Bridge onto a Small