Question

A block of mass m is placed on a rough horizontal surface. The coefficient of friction between them is μ. An external horizontal force is applied to the block and its magnitude is gradually increased. The force exerted by the block on the surface is R.

(a) The magnitude of R will gradually increase. 

(b) R ≤ mg √(μ² + 1).

(c) The angle made by R with the vertical will gradually increase. 

(d) The angle made by R with the vertical ≤ tan^-1 μ.

Answer 1

Correct Answer is: (a, b, c, & d)

R is the resultant of the normal reaction, N = mg, and the force of friction, F ≤ μmg. As P is increased, F (= P) increases, while N is constant.