Two blocks \(A\) and \(B\) of same mass \(M\) are connected with each other with an ideal string of length \(2l\) passing over an ideal pulley. The block \(A\) is connected to a light pan \(C\) with an ideal string as shown in figure. A particle of mass \(\frac{M}{2}\) is dropped on pan from height \(\frac{l}{2}\) as shown. If collision between particle and pan is plastic, acceleration of \(B\) just after the collision is?

Ans is \[\frac{g}{9}\].

Is this solution correct?

## Comments

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TopNewestMy Answer is a little different..

– Rohit Gupta · 2 years, 1 month agoLog in to reply

I think you guys would like to see this discussion. – Satvik Pandey · 2 years, 2 months ago

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@Nishant Rai

Although your answer is correct, the FBDs that you have drawn are not. You have missed out the gravitational force on \(A\). Due to this reason, you have skipped using \(T_1 -Mg=Ma\)

In reality, at the moment the mass strikes the pan:

\(T_1 = Mg + M\frac {v^2}{l}\)

And hence: \(T_1 -Mg=Ma=M\frac {v^2}{l}\)

Otherwise, you can also use constraint relations to get to same result. – Raghav Vaidyanathan · 2 years, 2 months ago

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– Satvik Pandey · 2 years, 2 months ago

I have a confusion. I think it is assumed that just after the collision block A performs a circular motion. But as soon as the block a A gets a tangential velocity it would have centripetal as well as a radial acceleration. How can we ignore that?Log in to reply

i have done the same thing, (this solution is not mine, this question came in mock paper of some coaching institute, they have provided this solution) – Nishant Rai · 2 years, 2 months ago

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– Raghav Vaidyanathan · 2 years, 2 months ago

Okay, but they aren't fully wrong, we can get everything without FBD itself...Log in to reply

– Nishant Rai · 2 years, 2 months ago

btw you are appearing for JEE ? are you enrolled in any coaching institute?Log in to reply

– Raghav Vaidyanathan · 2 years, 2 months ago

Yes, FIITJEELog in to reply

@satvik pandey – Raghav Vaidyanathan · 2 years, 2 months ago

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Can you please post the solution to Angular width of Refracted Beam!

Raghav Vaidyanathan – Nishant Rai · 2 years, 2 months ago

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@Raghav Vaidyanathan – Nishant Rai · 2 years, 2 months ago

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– Raghav Vaidyanathan · 2 years, 2 months ago

okLog in to reply

– Satvik Pandey · 2 years, 2 months ago

Could you please explain this answer?Log in to reply

@Raghav Vaidyanathan @Tanishq Varshney @Kushal Patankar Help! – Nishant Rai · 2 years, 2 months ago

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@satvik pandey i have made a note on this problem inviting views of other brilliant members(bc now even i am confused :/ ) – Nishant Rai · 2 years, 2 months ago

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– Satvik Pandey · 2 years, 2 months ago

Thanks for making it! :)Log in to reply

– Kyle Finch · 2 years, 2 months ago

Why wasn't \(T_1\) impulsive.😓Log in to reply