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Physics - Rotation Question with Solution | TestHub

PhysicsRotationCalculation of M.I.Easy2 minPYQ_2020

PhysicsEasynumerical

From a triangular lamina of side a and mass $m$ , a small triangular Lamina made by joining midpoints of sides of the triangular lamina is cut. The Moment of Inertia of complete Lamina about COM is $I_{o}$ . If the Moment of Inertia of remaining Lamina about the centroid is $\frac{p}{q} I_{0}$ , then find the value of $(p + q)$ . Where $p$ and $q$ are the least positive integers.

Answer:

31.00

Solution:

Dimension analysis

$I_{o} = K M a^{2}$

Now for small lamina

$I^{'} = K \frac{M}{4} {(\frac{9}{2})}^{2} = \frac{k m a^{2}}{16}$

$I^{'} = \frac{I_{o}}{16}$

So moment of Inertia of remaining part

$I_{L} = I_{o} - I^{'}$

$= I_{o} - \frac{I_{o}}{16}$

$I_{L} = \frac{15 I_{o}}{16}$

Subject:PhysicsTopic:RotationSubtopic:Calculation of M.I.

⏱ 2mℹ️ Source: PYQ_2020

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