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While catching a fast moving cricket ball, why do fielders gradually pull back their hands backwards with the moving ball? Please advice which among the following is the correct answer. If both are incorrect kindly give the correct answer:

A: By pulling the hands backward the fielder increases the time during which the high velocity of the moving ball decreases to 0. Thus, the acceleration of the ball is decreased and therefore the impact of catching the fast moving ball is also reduced.

B: By pulling the hand backwards, the fielder gradually and continuously decreases the momentum of the moving ball and thereby reducing the velocity to zero.

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closed as too localized by David Z Feb 9 '12 at 17:13

This question is unlikely to help any future visitors; it is only relevant to a small geographic area, a specific moment in time, or an extraordinarily narrow situation that is not generally applicable to the worldwide audience of the internet. For help making this question more broadly applicable, visit the help center.If this question can be reworded to fit the rules in the help center, please edit the question.

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Hi Ram, and welcome to Physics Stack Exchange! What are your thoughts on this? What have you tried to do to figure out the correct answer and why doesn't it work? If you edit your question to include that I'll be happy to reopen it. –  David Z Feb 9 '12 at 17:13
    
Dear David, I've already got a response to my question and the answer is in line with my thinking. Further, thank you for informing me that the question has been closed as it is too localized. I would appreciate if could kindly inform me what that means. For your very kind information, I am a student studying in class 9 in a school in India. Eagerly awaiting your response. –  Ram Sidharth Feb 9 '12 at 17:24
    
Actually A and B are the same thing.. –  Manishearth Feb 9 '12 at 18:21
    
Ram, the problem is that (1) this question is written in such a way as to be useless to anyone else who is not solving the exact same problem, and (2) you appear to have put no effort into it. Have a look at our homework policy for more information. –  David Z Feb 9 '12 at 18:50
    
Thank you for your responses. –  Ram Sidharth Feb 9 '12 at 19:36
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1 Answer 1

up vote 0 down vote accepted

If you consider the hands as the frame of reference, moving them backwards by accelerating negatively reduces the acceleration of the ball in that frame. Hence the impact of the ball (the force) is reduced (Newton's second law).

Let $\vec{a_1}$ be the acceleration of the ball in the initial frame of reference and $\vec{a_2}$ the acceleration of the hands. The resulting force with the hands moving backwards $\vec{F_{backwards}} = m*(\vec{a_1}-\vec{a_2}$) will be lower than the force without : $\vec{F} = m*\vec{a_1}$.

The fielder gradually absorbs energy from the ball to reduce the impact.

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Thanks for the answer –  Ram Sidharth Feb 9 '12 at 18:10
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