JEE Main 2025 — Rotational Motion Question with Solution
From: JEE Main 2025 (Online) 22nd January Morning Shift
Question
A uniform circular disc of radius ' and mass ' is rotating about an axis perpendicular to its plane and passing through its centre. A small circular part of radius is removed from the original disc as shown in the figure. Find the moment of inertia of the remaining part of the original disc about the axis as given above.
This question includes a diagram. The text above accompanies the figure.
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Show full solutionCorrect option: B
Step-by-step explanation
Mass of removed disc,
where, I = MOI of whole disc about perpendicular axis through O
I = MOI of removed dis about axis through O
(using parallel axis theorem)
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This is a previous-year question from JEE Main 2025, 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.