Speed after throwing something?

Question

Tony (of mass 55kg) coasts on his bicycle (of mass 5kg) at a constant speed of 5 m/s, carrying a 6kg pack. Tony throws his pack forward, in the direction of this motion, at 1 m/s relative to the speed of bicycle just before the throw. The initial momentum of the system (tony, bicycle, pack ) is 330 kg* m/s. The momentum of the system after the pack is thrown is 330 kg*m/s.

What is the bicycle speed after the throw? answer in kg*m/s

Answer 1

Linear momentum is conserved.

Initial momentum = (55 kg + 5 kg + 6 kg)(5 m/s) = 330 kg m/s

Final momentum = (55 kg + 5 kg)(v) + (6 kg)(6 m/s)

Set initial momentum = final momentum and solve for v.