A block is pushed upwards along the roof forming an angle a with the horizontal. The time of the ascent of the block to the upper point was found to be half the time of its descent to the initial point. Determine the coefficient of friction lit between the block and the roof.

A block is given certain upward velocity along the incline of elevation alpha . The time of ascent to upper point was found to be half the time of descent to initial point. The co-efficient of friction between block and incline is :

A block is at rest on an inclined plane making an angle alpha with the horizontal . As the angle alpha of the incline is increased the block starts slipping when the angle of inclination becomes theta . The coefficient of static friction between the block and the surface of the inclined plane is or A body starts sliding down at an angle theta to the horizontal. Then the coefficient of friction is equal to

A block is pushed up a rough inclined plane of 45^(@) .If the time of descent is three times the time of ascent,the coefficient of friction is ?

A wooden block is kept n a polished woden plank and the inclination of the plank is gradually increased. It is found that the block starts slipping when the pland makes an angle of 18^@ with the horizontal. However, once started the block can continue with uniform speed if the inclination is reduced to 15^@ . Find the coefficients of static and kinetic friction between the block and the plank.

A block begins to move on a rough horizontal surface with an initial velocity u. If it loses of its initial kinetic energy in time t, the coefficient of kinetic friction between the block and the surface is

Acceleration of block A varies with time as shown in figure the value of coefficient of kinetic friction between block A and B is

A rectangular block is kept on a rough horizontal surface and given some initial velocity. The coefficient of friction between the block and the surface is constant. The block will topple

A block is sliding on a rough horizontal surface. If the contact force on the block is sqrt2 times the frictional force, the coefficient of friction is