Physics · 2019
JEE Main · 10 January 2019, Shift 1 · Q7
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…
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 $\displaystyle \mu$, the torque, applied by the machine on the mop is :
Official answer
(4)
$\displaystyle \frac{2}{3} \mu \mathrm{FR}$
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JEE Main 2019 Physics question, with the answer from NTA’s final answer key. Where our answers come from.