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Physics - Rotation Question with Solution | TestHub

PhysicsRotationAngular momentumMedium2 minPYQ_2020

PhysicsMediumsingle choice

A particle executes uniform circular motion with angular momentum 'L'. Its rotational kinetic energy becomes half, when the angular frequency is doubled. Its new angular momentum is

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Solution:

(B) $K = \frac{1}{2} I ω^{2}, L = I ω$ $K^{'} = \frac{1}{2} I^{'} ω^{'2}, ω^{'} = 2 ω$ $∴ K^{'} = \frac{1}{2} I^{'} (2 ω)^{2}, K^{'} = \frac{K}{2}$ $∴ \frac{1}{2} (\frac{1}{2} I ω^{2}) = \frac{1}{2} I^{'} (2 ω)^{2}$ $∴ I^{'} = \frac{I}{8}$ $L^{'} = I^{'} ω^{'} = \frac{I}{8} \times 2 ω = \frac{I ω}{4} = \frac{L}{4}$

Stream:MHT_CETSubject:PhysicsTopic:RotationSubtopic:Angular momentum

⏱ 2mℹ️ Source: PYQ_2020

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