Answer: 2mg/(M+2m).
- A 2mg/(M+2m)
- B mg/(M+m)
- C mg/M
- D 2mg/M
Correct answer: A. 2mg/(M+2m)
Explanation: Net torque on cylinder = mR - 0 = (MR²/2)α. Also a = Rα and T = m(g-a). Solving: T = mRg/(2m+M) x M/R, and a = 2mg/(M+2m).
Torque about axis O equals the force F multiplied by the perpendicular distance r⊥ from the axis to the line of action of the force, producing rotation.
Concept context
Moment of inertia, torque, angular momentum, rolling motion. Very high JEE weightage.
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