Question

A ball of mass 100 gram travelling horizontally with an initial velocity of 50m/s, strike the stationary wall and rebound with same speed. calculate: (a) the change in momentum of the ball (b) if the ball remains in contact with wall for 0.001 second , calculate the force exerted by on the wall.

Answer 1

Initial velocity (v) = - 50 m/s

Final velocity (u) = 50 m/s

Mass of the ball = 100 grams = 0.1 kg

a) change in momentum = Final momentum - Initial momentum

$= 0.1 \times ( 50 - (-50))$

$= 0.1 \times 100$

Change in momentum = 10 kg m/s

b) Force = Rate of change of momentum

$F = \frac{10}{0.001}$

F = 10000 N

Hence, the force applied by the wall is 10000 N