Rotational Motion

JEE Main level, single correct, medium

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Question 1 of 280

A solid sphere and a thin uniform circular ring have identical mass MM and radius RR. The ratio of their moments of inertia about their respective central diameters is:

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Answer: (B) 4:54:5

For solid sphere, I1=25MR2I_1 = \frac{2}{5} M R^2. For ring about diameter, I2=12MR2I_2 = \frac{1}{2} M R^2. Ratio =2/51/2=45= \frac{2/5}{1/2} = \frac{4}{5}.

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