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Two friends A and B (each weighing 40 kg...

Two friends A and B (each weighing 40 kg) are sitting on a frictionless platform some distance d apart. A rolls a ball of mass 4 kg on the platform towards B which B catches. Then B rolls the ball towards A and A catches it. The ball keeps on moving back and forth between A and B. The ball has a fixed speed of 5 m/s on the platform. a. Find the speed of A after he rolls the ball for the first time. b. Find the speed of A after he catches the ball for the first time. c. Find the speed s of A and B after the ball has made 5 round trips and is held by A. d. How many times can A roll theball? e. where is the centre of mas the system A+B+ ball at the end of the nth trip?

A

`(10)/(11)d`

B

`(10)/(21)d`

C

`(50)/(11)d`

D

None of these

Text Solution

Verified by Experts

The correct Answer is:
B

from linear momentum conservation
`M_(A)V=m_(b)5rArr v=(4xx5)/(40)=0.5m//sAns.`
`F_(e x t)=0`, Centre of mass of system cannot move Initial position of centre of mass of `A`.

`X_(cm)=(40d)/(44+40)=(10)/(21)d`
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