Question

A ball of mass 20g hits a wall at an angle of 45° with a velocity of 15 m/s. If the ball rebounds at 90° to the direction of incidence, calculate the impulse received by the ball.

Answer 1

Let's consider the momentum vectors before & after hitting.

As we know,

Impulse=Change in momentum

I=mv'-mv

=(mvcos45+mvsin45)-(mvcos45-mvsin45)

[since, vertical resolution cancel out and horizontal adds up]

=2mvsin45

=2*0.02*15*sin45

=0.424 N-s