A block of mass 0.1 kg is held against a wall applying a horizontal force of 5 N of 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
0.98 N
Since the block is stationary, friction balances the weight of the block.
Hence, f = mg = 0.1 × 9.8 = 0.98 N