● The force of frictionalways acts in a direction opposite to that in which the body tends to move, which means against the direction of the force.
The amount of friction is exactly equal to the force that appears to move the body, before the limiting value is reached.
The restricting friction magnitude bears a constant ratio between the two surfaces to the natural reaction.
Friction force is dependent on surface roughness / smoothness
The frictional force is independent of the contact area between the two surfaces .
Extra facts:
Electrostatic force:
The electrostatic force, also known as the Coulomb Force, is an attractive and repulsive force induced by its electric charges between particles.
This Coulomb Interaction is named after Charles-Augustin de Coulomb, a French physicist.
The Electrostatic Force is one of nature's four basic forces. We make use of the Coulomb Law to overcome the forces generated by charging configurations.
Magnetic force:
Magnetic force, attraction or repulsion which occurs because of their motion between electrically charged particles.
The magnetic force between two moving charges can be defined as the effect that one magnetic field produced by the other exerts on either charge.
Force of gravity:
● The Universal Law of Gravitation says that any two objects having mass will attract each other with a force which is directly proportional to the product of their masses.
● This force is also inversely proportional to the square of the distance between their centers.