Advance Illustrations – A Rough Block Projected Over Another Block | NLM #36 for JEE Advanced

Questions asked in JEE Advanced are based on critical thought processes rather than direct application of concepts. For preparation of JEE Advanced, students have to focus on problems based on multi concept applications.

Ashish Arora Sir has taken up a case of A Rough Block Projected Over Another Block which is important for select in IIT.

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[TargetIITBatch]

There is one more concept of COM
people who apply center of mass concept here will notice that the block 2m is only moving 10/3 m if seen from the ground and will just use kinemaitc equation for acceleration of this block =g/2 and s = 10/3 will get wrong answer as they are just mixing information of the 2 frames one is wrt m and other is wrt ground ... so the question will actually become much more complex
so much better to not use ground frame insted use the block m frame which is much easier

[inferno]

If B starts moving shouldn't there be pseudo force on A?

[aakanksha]

Pseudo force on a body
=(acc. of frame of reference)*(mass of the body on which pseudo force is applied)

[RoyBoyLab]

After doing this question , , do HCV Q 31

[vanshrajsingh]

Sir i have confusion that since there is no real force on b it should not move and there will not be slipping since a is given only velocity
Plz clarify

[adityamahesh]

sir dont we have to consider velocity of block b and put velocity of a relative to b in equation of motion?

[vivekmeena]

Sir what happen when we take a time depending velocity at same conditions.

[shivankrastogi]

sir cant we do this question by work done by friction = change in kinetic energy (where final kinetic energy of 2m = zero)

[mdrehan]

Sir here why we hv taken relative acceleration b/w blocks A & B