A mass m moves with a velocity v and collides inelastically with another identical mass at rest. After collision, the first mass moves with velocity `v/(sqrt3)` in a direction perpendicular to Before collision the initial direction of motion. The speed of the `2^(nd)` mass after collision 

Options

A. `(2v)/(sqrt3)`
B. `v/(sqrt3)`
C. `v`
D. `sqrt(3)v`

Answer

A

Explanation

In x-direction `mv + 0 = 0 + mv_1 cos theta " " ….(i)`
where `v_1` is the velocity of `2^(nd)` mass.
In y-direction
`0 = (mv)/(sqrt3) - mv_1 sin theta`
or `mv_1 sin theta = (mv)/(sqrt3) " " …….(ii)`
Squaring and adding equs. (i) and (ii), we get
`v_1^2 = v^2 + (v^2)/(3) = (4v^2)/(3) :. v_1 = (2v)/(sqrt3)` .