Why a fielder in the ground gradually pulls his hands backward while catching a fast moving cricket ball ?
- A.To reduce the acceleration of the ball
- B.To increase the acceleration of the ball
- C.To increase the velocity of the ball
- D.None of above
Correct answer
Explanation
The correct answer is A, to reduce the acceleration of the ball. Pulling the hands back stretches the time in which the ball stops, so its deceleration and the force on the hands become smaller.
The ball's momentum has to fall from mv to zero, and that change is fixed. By Newton's second law, force equals change in momentum divided by the time taken (F = Δp/Δt). When the fielder moves the hands back, the stopping time increases, so the ball slows down more gently, its rate of change of velocity (acceleration, here retardation) falls, and the force on the palms falls with it. That is why the catch does not hurt. The same idea is used in shock absorbers and in the sand pit for long jumpers.
B is wrong because a larger acceleration would mean a bigger force and a painful catch.
C is wrong because the fielder is trying to stop the ball, not speed it up.
D is wrong because option A gives the right reason.
Exam tip: more stopping time, less force: F = Δp/Δt explains catches, airbags and sand pits.
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