JEE Main 2021 — Rotational Motion Question with Solution
From: JEE Main 2021 (Online) 17th March Morning Shift
Question
A mass M hangs on a massless rod of length l which rotates at a constant angular frequency. The mass M moves with steady speed in a circular path of constant radius. Assume that the system is in steady circular motion with constant angular velocity . The angular momentum of M about point A is LA which lies in the positive z direction and the angular momentum of M about point B is LB. The correct statement for this system is :
This question includes a diagram. The text above accompanies the figure.
Choose an option
Show full solutionCorrect option: A
Correct answer
ALA is constant, both in magnitude and direction
Step-by-step explanation
Net force on M is towards A, hence torque is zero
about A.
as so LA = constant
as so LA = constant
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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.