JEE Main 201910 Jan, Morning shiftPhysicsMediumRotational Motion140× since 2002
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 -