A body of mass `M` moves with velocity `v` and collides elasticity with another body of mass `m(M gt gt m)` at rest , then the velocity of the body of mass `m` is

Options

A. `v`
B. `2 v`
C. `v//2`
D. Zero

Answer

B

Explanation

`Mv = Mv_(1) + Mv_(2)` (i)
`v_(1) + v = v_(2)` (ii)
`rArr v_(1) = v_(2) - v in (i)`
`Mv = M(v_(2) - v) + mv_(2)`
`2 Mv = (M + m)v_(2) rArr v_(2) = ( 2Mv)/(M + m)`
Since `m lt lt M , v_(2) = 2v`