Question

Question 37:
(a) Explain why, a cricket player moves his hands backwards while catching a fast cricket ball.
(b) A 150 g ball, travelling at 30 m/s, strikes the palm of a player’s hand and is stopped in 0.05 second. Find the force exerted by the ball on the hand.

Lakhmir Singh Physics Class 9

Answer 1

a) The cricketer does this to lower the force. When the player brings his hands backwards, it helps is increasing time of the force action. So as the time increases, the force also gets reduced and the player does not get injured in his hands.

b) Given,

Mass = 150 g

Now, we shall convert it into kg.

m = 0.15 kg

The starting velocity is 30 m/s

So,

Starting momentum = 0.15 x 30 = 4.5 kgm/s

Final value of momentum = 0

Change occured for momentum = 0 - 4.5

• Change occured for momentum = 0 - 4.5 = -4.5kgm/s

Momentum's rate of change will be =

-4.5/0.05

-90 N

The value of the force exerted is 90 N

Answer 2

✰ Question Given :

• ⇒ (a) Explain why, a cricket player moves his hands backwards while catching a fast cricket ball.

✰ Required Solution :

• ⇒ While catching a fast moving cricket ball, a fielder in the ground gradually pulls his hand backward because by doing this, he increases the time in which the velocity of ball will become zero.

• ⇒ Thus, the rate of change of momentum will be large and less force will be exerted by the ball on the hand of the fielder.

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