Question

A ball of mass ' m' moves normal to a wall with a velocity 'u' and rebounds with a velocity 'v' .The change in momentum of the ball during the rebounding is​

Answer 1

Answer:

Let us say the ball is moving in the direction of positive X axis.

Momentum of ball before colliding with the wall = mass * velocity = p1 = m u

 Momentum is in the direction of +ve x axis.

After rebounding let us say the ball moves back with a speed v. Since the ball moves in the negative x direction (after reflection) , we denote it as -v.

Its momentum after rebounding is p2 = =  - mv       

Change in the momentum during the rebounding is

              = final momentum -  initial momentum  = p2 - p1 =

               =  (- m v ) - (m u)  = -  m v - m u = -m ( v+u)

The change in momentum is a vector quantity and is in - ve x direction.

Answer 2

Answer:

p= m x v

p = momentum

m = mass

v = velocitiy