JEE Main 2021PhysicsRotational MotionMediumMCQ

JEE Main 2021 — Rotational Motion Question with Solution

JEE Main 2021 (26 Feb Shift 2)

Question

A cord is wound round the circumference of wheel of radius r, The axis of the wheel is horizontal and the moment of inertia about it is I. A weight mg is attached to the cord at the end. The weight falls from rest. After falling through a distance h, the square of angular velocity of wheel will be

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Show full solutionCorrect option: A
Correct answer
A2mghI+mr2

Step-by-step explanation

mgh=12Iω2+12mv2

v=ωr

mgh=12Iω2+12 mω2r2

2mghI+mr2=ω2

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About this question

This is a previous-year question from JEE Main 2021, 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.