JEE Main 2018PhysicsRotational MotionMediumMCQ

JEE Main 2018 — Rotational Motion Question with Solution

JEE Main 2018 (08 Apr)

Question

Seven identical circular planar disks, each of mass M and radius R are welded symmetrically as shown. The moment of inertia of the arrangement about the axis normal to the plane and passing through the point P is:

Choose an option

Show full solutionCorrect option: A
Correct answer
A1812MR2

Step-by-step explanation

The motion of inertia of the system about O,

12MR2+6×12MR2+6×M×2R2

⇒   I1=72MR2+24MR2

The motion of inertia of the system about P, 

⇒   I1+7MD2

⇒    72MR2+24MR2+7M×3R2

⇒   1812MR2

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About this question

This is a previous-year question from JEE Main 2018, covering the Rotational Motion chapter of Physics. PrepSharp catalogues every PYQ from JEE Main with a verified answer key and step-by-step solution prepared by IIT alumni — so you can search by chapter, topic or year and revise efficiently.