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A boy of mass 40 kg stands on a rail roa...

A boy of mass `40 kg` stands on a rail road car of mass `60 kg`, moving with velocity `10 m//s`. Now , the boy begins to run with velocity `5 m//s` , with respect to the car , in the same direction , the velocity of the car will be

A

`6 m//s`

B

`8 m//s`

C

`10 m//s`

D

`12 m//s`

Text Solution

Verified by Experts

The correct Answer is:
B
`(40 + 60)v_(0) = 40(u + v') + 60 v'`
`100 xx 10 = 40(5 + v') + 60 v' rArr v' = 8 m//s`
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