A particle of mass m moving towards the east with speed v collides with another particle of the same mass and same speed v moving towards the north. If the two particles stick to each other, the new particle of mass 2m will have a speed of 

Options

A. `v`
B. `v/2`
C. `v/(sqrt2)`
D. `vsqrt(2)`

Answer

C

Explanation

It is a case of perfectly inelastic collision.
According to law of conservation of linear momentum, we get
`m^2 v^2 + m^2v^2 = (2 mV)^(2)`
where V is the common velocity after the collision.
Solving , we get , `V = v/(sqrt2)`.