Question

A cricket ball of mass 150g is moving with a velocity of 12m/s and is hit by a bat, so that the ball is turned back with a velocity of 20m/s. The force of the blow acts for 0.01s on the ball. Find the average force exerted by the bat on the ball.

Answer 1

We know that Force = Impulse/ Time

Impulse = mass * change in velocity

Time = 0.01 s

Mass m = 150 g = 1.5 x 10 ̄ ¹ kg

Change in velocity = Final - intial velocity = 20 - (-12) = 32 m/s

Therefore Force = mass * change in velocity / time = 1.5 x 10 ̄ ¹ x 32 / 0.01

= 15 x 32 = 480 N

Average force on the ball is 480 N

Answer 2

Here, we have

Mass of the ball, m = 150 g = 0.15 kg

Initial speed of the ball, u = -12 m/s

Final speed of the bal after being hit, v = 20 m/s

Impulse = change in momentum = final momentum initial momentum

= Impulse = 0.15 × 20 0.15 × (-12) = 4.8 Ns