Question

(a)Explain why a player lowers his hands while catching a cricket ball.
(b)Explain the use of seat belts in cars.

Answer 1

1. Why does a player lower his hand while catching a cricket ball ?

Answer:

First of all, you should know the Concept of Momentum change. Rate of change of momentum denotes Force experienced.

$force = \dfrac{ \Delta p }{ \Delta t}$

p => momentum and t = time

So when the player lowers hand while catching the ball, he actually increases the time over which the momentum is decreased to zero.

Hence ∆t increases .

As a result the force experienced on the hands decreases. This prevents any injury to the hands.

Explain the use of seatbelts in cars?

Answer:

Seat belts restrain the body from hitting any front objects like steering wheel or dashboard in case of rapid deceleration.

Seatbelts are also wide straps. This increases the area over which the force (due to retardation) is spread. As a result the pressure also decreases. This prevents any injury to the chest region.