a boy of mass 60 kg running at 3m/s jumps on to a trolley of mass 140 kg moving with - Science - Motion

Question

a boy of mass 60 kg running at 3m/s jumps on to a trolley of
mass 140 kg moving with a velocity of 1 5m/s in the same direction
what is their common velocity please answer this question

Rahul Verma · Accepted Answer

Initial momentum of the system = momentum of the boy + momentum of
the trolley = 60 Ã— 3+ 140 Ã— 1
5

=> Î”P 
1 = 180 +
210 = 390 Ns

Final momentum of the system, Î”P 
2 = mass
of the boy and trolley Ã— common
velocity

=> Î”P 
2 =
(60+140)v = 200v

By law of conservation of momentum,

Î”P 
1 =
Î”P 
2

=> 390 = 200v

=> v = 1 95 m/s

a boy of mass 60 kg running at 3m/s jumps on to a trolley of mass 140 kg moving with a velocity of 1.5m/s in the same direction. what is their common velocity. please answer this question.