Topic: Moment of inertia, radius of gyration, MI of simple objects· Rotational Motion

Three objects, A : (a solid sphere), B : (a thin circular disk) and C : (a circular ring), each have the same mass M and radius R. They all spin with the same angular speed ω about their own symmetry axes. The amounts of work (W) required to bring th…

Three objects, A : (a solid sphere), B : (a thin circular disk) and C : (a circular ring), each have the same mass M and radius R. They all spin with the same angular speed \(\omega\) about their own symmetry axes. The amounts of work (W) required to bring them to rest, would satisfy the relation

1. \(W_C>W_B>W_A\)

2. \(W_B>W_A>W_C\)

3. \(W_A>W_B>W_C\)

4. \(W_A>W_C>W_B\)

Doubtly Asked 30 Oct 2026 NEET UG 2018 Practice test neet Save WhatsApp Report

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Answer: 1. \(W_C>W_B>W_A\)

Work needed to stop each body equals its rotational kinetic energy, \(W=\tfrac12I\omega^2\). Same \(M\), \(R\), \(\omega\), so \(W\propto I\).

Solid sphere A: \(I=\tfrac25MR^2\)
Thin disk B: \(I=\tfrac12MR^2\)
Ring C: \(I=MR^2\)

So \(I_C>I_B>I_A\) and therefore \(W_C>W_B>W_A\).

Doubtly AI · 30 Oct 2026 AI-generated · not yet verified Report

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Three objects, A : (a solid sphere), B : (a thin circular disk) and C : (a circular ring), each have the same mass M and radius R. They all spin with the same angular speed ω about their own symmetry axes. The amounts of work (W) required to bring th…

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