In this session we are going to deal a special type of force called friction....friction is the special type of force which is defined as the resistance that one surface or object encounters when moving over the other.
The causes of the restive force of friction are molecular adhesion, surface roughness, and the plowing effect. Adhesion is the molecular force resulting when two materials are brought into close contact with each other. Trying to slide objects against each other requires breaking these adhesive bonds.