To mop-clean a floor, a cleaning machine presses a circular mop of radius 
vertically down with a total force 
and rotates it with a constant angular speed about its axis. If the force 
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:
A
B
C
D
Text Solution
Verified by ExpertsThe correct answer is:
D
JEE Main 2019
Consider a strip of radius 
and thickness 
, Torque due to friction on this strip Net torque 
Torque on ring
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