Q6.10: NCERT Physics - Part 1 SYSTEMS OF PARTICLES AND ROTATIONAL MOTION 6.10 Solution: Torques of equal magnitude are applied to a hollow cylinder and …

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Q6.10: NCERT Physics - Part 1 SYSTEMS OF PARTICLES AND ROTATIONAL MOTION 6.10 Solution: Torques of equal magnitude are applied to a hollow cylinder and …

⚠️ Common Exam Traps & Conceptual Pitfalls

Students often confuse the moment of inertia of a solid sphere ($\frac{2}{5}MR^2$) with that of a hollow sphere ($\frac{2}{3}MR^2$) or misremember the coefficient for a hollow cylinder ($MR^2$). Always verify the specific geometric shape and axis of rotation, as the solid sphere's lower inertia coefficient ($0.4$ vs $1.0$) is the sole reason it achieves a higher angular speed under equal torque.

Torques of equal magnitude are applied to a hollow cylinder and a solid sphere, both having the same mass and radius. The cylinder is free to rotate about its standard axis of symmetry, and the sphere is free to rotate about an axis passing through its centre. Which of the two will acquire a greater angular speed after a given time?