A block of mass 0.1 kg is held against a wall applying a horizontal force of 5 N on the block…

Q: A block of mass 0.1 kg is held against a wall applying a horizontal force of 5 N 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

(a)2.5 N

(b)0.98 N

(c)4.9 N

(d)0.49 N

Ans: (b)

Sol: fmax = u N = 0.5 × 5= 2.5 N

Force due to weight = mg = 0.1×9.8 = 0.98 N

As , 0.98 < 2.5 Hence , frictional force = 0.98 N