JEE Main 2019 — Rotational Motion Question with Solution
From: JEE Main 2019 (Online) 10th January Morning Slot
Question
To mop-clean a floor, a cleaning machine presses a circular mop of radius R vertically down with a total force F and rotates it with a constant angular speed about its axis. If the force F is distributed uniformly over the mop and if coefficient of friction between the mop and the floor is , the torque, applied by the machine on the mop is -
Choose an option
Show full solutionCorrect option: D
Correct answer
DFR
Step-by-step explanation
Consider a strip of radius x & thickness dx,
Torque due to friction on this strip.
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This is a previous-year question from JEE Main 2019, 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.