Rotation 5 Question 30
42. A carpet of mass made of inextensible material is rolled along its length in the form of a cylinder of radius and is kept on a rough floor. The carpet starts unrolling without sliding on the floor when a negligibly small push is given to it. Calculate the horizontal velocity of the axis of the cylindrical part of the carpet when its radius reduces to .
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Answer:
Correct Answer: 42.
Solution:
- Let
be the mass of unwound carpet. Then,
From conservation of mechanical energy :
or
or