A body of mass m1 is moving with a velocity 'v'. It collides with another stationary body of mass m2. They get embedded. At the point of collision, the velocity of the system is
Decreases but does not become zero
By momentum conservation before and after collision.
m1V+m2×0=(m1+m2)v⇒v=m1m1+m2V i.e.
Velocity of system is less than 'v' .