Question
A body of mass m1 moving with velocity 
collides with target of mass 
at rest. Can the mass 
move with velocity opposite to the direction of 
after collision? Explain. (Let collision be elastic collision).
Solution
In an elastic collision,
If the mass m1 of the moving ball is greater than the mass m2 of the ball at rest, then after collision both the velocities v1 and v2 will be positive. And two balls will move in the same direction.
And, if the moving ball is lighter than the ball at rest, the two balls will move in the opposite direction.
