A sphere of mass M moving with velocity w collides elastically with another of mass m at rest. After collision their final velocities are V and v. The value of vis:

Options

A. `(2Mu)/(m)`
B. `(2mu)/(M)`
C. `(2u)/(1+(m)/(M))`
D. `(2u)/(1+(M)/(m))`

Answer

c

Explanation

Applying conservation of momentum
Mu=MV+mv
Also as collison is perfectly elastic.
`(v-V)/(u-0)=e=1`
or u-V=u or v-u=V
Puttting in (i) Mu=M(v-u)+mv
or 2 Mu=(M+m)v or `v=(2Mn)/(M+m)`