Physics - Rotation Question with Solution | TestHub

PhysicsRotationCalculation of M.I.Easy2 minPYQ_2020
PhysicsEasysingle choice

An equilateral triangleABCis cut from a thin solid sheet of wood. (See figure)D, EandFare the mid-points of its sides as shown andGis the centre of the triangle. The moment of inertia of the triangle about an axis passing throughGand perpendicular to the plane of the triangle isI0. If the smaller triangleDEFis removed fromABC,the moment of inertia of the remaining figure about the same axis isI.Then:

Options:

Answer:
B
Solution:

Dimension analysis

Io=KMa2

Now for small lamina

I=KM4a22=kma216

I=Io16

So moment of Inertia of remaining part

IL=Io-I

=Io-Io16

IL=15Io16

Subject:PhysicsTopic:RotationSubtopic:Calculation of M.I.
2mℹ️ Source: PYQ_2020

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