Question

A body of mass M moving with velocity 3km/h colloide with a body of mass 2M at rest. Now the coalesced mass start to move with a velocity is........?

Answer 1

Using Conservation of momentum for perfectly Inelastic collision,

M1v1 + M1v2 = (M1+M2)V'

Here v2 will be 0 as the body of mass 2m is in rest.
We have to calculate V' which is combined velocity of coalesced mass.

Hope you get your answer.