Question

Tony (of mass 45 kg) coasts onhis bicycle (of mass 20 kg) at a constant speedof 1 m/s, carrying a 13 kg pack. Tonythrows his pack forward, in the direction of hismotion, at 6 m/s relative to the speed ofbicycle just before the throw. A)What is the initialmomentum of the system (Tony, the bicycle, and thepack)? Answer in units of kg · m/s. B) What is the momentum of the system im- mediately after the pack isthrown? Answer in units of kg· m/s. C) What is the bicycle speedimmediately after the throw? Answer in units ofkg · m/s

Answer 1

As we can say that momentum will ne conserved.
Assume speeds (V) relative to ground to all objects
So the resulting speed of the pack, will be 6-1
=5 m/s

Assume forward to be positive direction

for convenience assume bike and rider as M1 and the pack as M2
M1V1 + M2V2 = M1V3 + M2V4
65(1) + 13(1) = 65 V3 + 13(5)
Initial momentum is the left side of equation = 78 kg*m/s
2)
momentum is conserved so it's still 78 kg*m/s
3)
now we solve for V3
78 = 65 V3 + 65
65 V3 = 13
V3 = = 13/65 = 0.2/ ms
still going forward but more slowly