Exams › JEE Advanced › Physics
A ring of mass m rests on a horizontal surface. A body of equal mass m is connected via a string wound around the ring. When the system is released from rest, the ring rolls without slipping. Examine the following statements: (i) The acceleration of the centre of mass of the ring is 2g/3. (ii) The acceleration of the hanging body is 4g/3. (iii) The friction force on the ring acts in the forward direction (direction of motion). (iv) The friction force on the ring acts in the backward direction. Which combination is correct?
- Statements (i) and (ii) only
- Statements (i) and (iii) only
- Statements (ii) and (iv) only
- None of these
Correct answer: None of these
Solution
Solving the coupled equations yields a_cm = g/3 (not 2g/3) and a_hanging = 2g/3 (not 4g/3), and friction acts forward. Since both (i) and (ii) are wrong in their stated values, none of the given combinations is fully correct.
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