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 ` mu ` the torque, applied by the machine on the mop is:

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 the floor is mu , the torque, applied by the machine on the mop is :

In Fig. 7.149 , coefficient of friction between the block and the floor is mu . Force F that will move the block on the floor with a uniform speed is :

You want to apply a force on a box so that it moves with constant speed across a horizontal floor. The coefficient if kinetic friction between the box and the floor is mu_(k). Of the flur following cases, the force you apply on the box will be smallest when you

A horizontal force F pulls a 20 kg box at a constant speed along a horizontal floor. If the coefficient of friction between the box and the floor is 0.25,how much work is done by the force F in moving the box through a distance of 2 m?

A horizontal force F pulls a 20 kg box at a constant speed along a rough horizotal floor. The coefficient of friction between the box and the floor is 0.25. The work done by force F on the block in displacing it by 2 m is

A uniform solid cylinder of mass m rests on two horizontal planks. A thread is wound on the cylinder. The hanging end of the thread is pulled vertically down with a constant force F . Find the maximum magnitude of the force F which may be applied without bringing about any sliding of the cylinder, if the coefficient of friction between the plank and the cylinder is equal to mu . What is the maximum acceleration of the centre of mass over the planks?

A disc of radius R rotates from rest about a vertical axis with a constant angular acceleration such that a coin placed with a tangenitial between a as shown in figure If the coefficient of static friction between the coin and disc is mu_(s) .Find the velocity of the before it start sliding relative as the disc

A hollow sphere of radius r is rotating about a horizontal axis at some angular speed omega_(0) . It is gently lowered to ground and the coefficient of friction between sphere and the ground is mu .How far does the sphere move before it starts pure rolling?

A uniform solid cylinder of mass m rests on two horizontal planks. A thread is wound on the cylinder. The hanging end of the thread is pulled vertically down with a constant force F(figure). Find the maximum magnitude of the force F which still does not bring about any sliding of the cylinder, if the coefficient of friction between the cylinder and the planks is equal to k. What is the acceleration w_(max) of the axis of the cylinder rolling down the inclined plane?