16.Brakes of a very small contact area are not used, although friction is independent of area. It is because friction:

17.A block is released from top of a smooth inclined plane. It reaches the bottom of the plane in 6 s. The time taken by the body to cover the first half of the inclined plane is:

18.Mark correct option or options.

19.A light spring balance hangs from the hook of the other light spring balance and a block of mass M kg hangs from the former one. Then the true statement about the scale reading is:

20.A block of mass 0.1 kg is held against a wall by applying a horizontal force of 5N on the block. If the coefficient of friction between the block and the wall is 0.5, the magnitude of the frictional force acting on the block is: