A board is balanced on a rough horizontal semi-circular log. Equilibrium is obtained with the help of addition of a weight to one of the ends of the board when the board makes an angle `theta` with the horizontal. Coefficient of friction between the log and the board is

The length of a uniform ladder of mass m is 1. It leans against a smooth wall making an angle theta with the horizontal. What should be the force of friction between the floor and ladder so that the ladder does not slip ?

A rough vertical board has an acceleration a so that a 2 kg block pressing against it dows not fall. The coefficient of friction between the block and the board should be

A rough vertical board has an acceleration a so that a 2 kg block pressing against it dows not fall. The coefficient of friction between the block and the board should be

A block of weight 200N is pulled along a rough horizontal surface at constant speed by a force 100N acting at an angle 30^(@) above the horizontal. The coefficient of friction between the block and the surface is

A particle of mass m strikes a horizontal smooth floor with velocity u making an angle theta with the floor and rebound with velocity v making an angle theta with the floor. The coefficient of restitution between the particle and the floor is e . Then

A block A of mass 5 sqrt( 3) m rests on a rough horizontal plane relative to which its coefficient of friction is mu A light string attached to this block passes over a light frictionless pulley and another block B of mass m hangs from it. It is observed that the block A just slips when the string makes an angle of 60^(@) with the horizontal . Find the coefficient of static friction between the block A and the plane. If the same force acting through the sting is applied to the block A in the horizontal direction, find the acceleration of the block A.

A block of mass 10 kg is placed on the rough horizontal surface. A pulling force F is acting on the block which makes an angle theta above the horizontal. If coefficient of friction between block and surface is 4/3 then minimum value of force required to just move the block is (g = 10 m/s^2)

A block of mass m slides down an inclined plane which makes an angle theta with the horizontal. The coefficient of friction between the block and the plane is mu . The force exerted by the block on the plane is

A block of mass m lying on a rough horizontal plane is acted upon by a horizontal force P and another force Q inclined at an angle theta to the vertical. The minimum value of coefficient of friction of friction between the block and the surface for which the block will remain in equilibrium is