Equilibrium of a body lying on a horizontal plane:
We know that a body lying on a rough horizontal plane will remain in equilibrium. But whenever a force is applied to it, the body will tend to move in the direction of the force. In such cases, the equilibrium of the body is studied first by resolving the forces horizontally and then vertically.
Now the value of the force of friction is obtained from the relation:
F = µR
Where, µ = Coefficient of friction
R = Normal reaction