JEE Main 2021 — Rotational Motion Question with Solution
From: JEE Main 2021 (Online) 27th August Evening Shift
Question
Two discs have moments of inertia I1 and I2 about their respective axes perpendicular to the plane and passing through the centre. They are rotating with angular speeds, 1 and 2 respectively and are brought into contact face to face with their axes of rotation coaxial. The loss in kinetic energy of the system in the process is given by :
Choose an option
Show full solutionCorrect option: C
Correct answer
C
Step-by-step explanation
From conservation of angular momentum we get
Solving above we get
Solving above we get
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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.