I dunno why, but it said that it won't let me post this answer, tho it never contained any rude words! So, here I'm posting this screenshot of the answer, apologies for the inconvenience caused!

I tried to express myself in the easiest way I could. But if you've still got a doubt, I can't help it cuz brainly.in has banned all the means of communication. But, don't worry. If you still have a doubt, you can text me on my MySpace account - @William.Franklin for any further assistance.

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Given that a uniformly moving cricket ball turned back by hitting it with a bat for a very short time-interval.

So in this case we are discussing the variation of acceleration with time.

To avoid the confusion, Please read the given below points:

• Initially the ball is moving with  certain Constant velocity .  As the bat strikes the ball ,a collision occurs between a bat and ball which last for very short duration of time.
• In this collision, the bat imparts a huge impulsive force on the ball which changes its direction and gain speed. [ As we know that when force acts on object, it can change its speed and direction]
• Acceleration of ball is just zero before it strikes the ball, but as it strikes the bat, it gets accelerated due to the impulsive  force given by the bat. So, the ball returns back with the same speed .
• If we plot the graph , for the above situation, we get the similar graph as shown in the attachment. Initially the ball is with uniform velocity , so acceleration is zero. indicated by A in graph. The bat hits the ball, due the impulsive force acting on the ball, there is sudden increase in its acceleration for a short period of time Δt  . Then the ball returns in the opposite direction with same speed [uniform velocity ] hence acceleration is zero indicated by C.
• I hope its clear .