Laws of Friction:

Consequently studies carried out by Coulomb in the year 1781, he reported that:

1. The total amount of friction that can be developed is independent of the magnitude of the area of contact.

2. The total frictional force that might be developed is proportional to the normal force transmitted across the surface of contact.

3. For low velocities, the total amount of friction that can be produced is practically independent of velocity. Though, it is less than the frictional force corresponding to impending motion.

Let a body of weight W resting on a floor. Consider P be the force applied as shown in Figure. As forces P and W are concurrent, there must be a third force, equal in magnitude and opposite in nature of the resultant of P and W, to keep the body in equilibrium. Consider it be denoted by R. The normal and frictional (here, horizontal) components of R are represented by N and F, respectively.