A ball of 15 kg is kept-at a horizontal surface. To make it move at least 30 N force is to be acted upon that body. What is the value of the coefficient of friction?

To set a body mass 5 kg in motion over a horizontal surface a minimum force of 30 N has to be applied. What is the value of the coefficient of friction?

A car of mass 1500 kg is moving with a speed of 12.5 m cdot s^(-1) on a circular path of radius 20 m on a level road. What should be the frictional force between the car and the road so that the car does not slip? What should be the value of the coefficient of friction this force?

A block is placed on a horizontal surface. The block is pushed by applying a force F which acts at an angle of theta with the vertical. How much force will be required to move the block if frictional coefficient mu ? Discuss the fact if tan theta< mu .

A body of mass 2 kg is pulled with a velocity 2 m cdot s^(-1) on horizontal surface. What will be the heat produced in 5s, if the coefficient of friction between the body and the surface is 0.2? Given, J = 4.2 J cdot cal^(-1) , g = 9.8 m cdot s^(-2) .