The smoothness of the contacting surfaces influences friction. If two surfaces are rough than if they are smooth, then is important to action witha greater force. However, friction decreases with smoothness only to a degree; friction actually increases between two extremely smooth surfaces because of increased attractive electrostatic forces between their atoms. Friction does not depend on the amount of surface area in contact between the moving bodies or (within certain limits) on the relative speed of the bodies. It does, however, depend on the magnitude of the forces holding the bodies together. When a body is moving over a horizontal surface, it presses down against the surface with a force equal to its weight, i.e., to the pull of gravity upon it; an increase in the weight of the body causes an increase in the amount of resistance offered to the relative motion of the surfaces in contact.
When we move an object on any surface, we can feel a opposing force forcing the object to stop, this opposing force is known as friction. Friction is greater on rough surfaces as these surface have a lot of bumps and ridges. Where as friction on smoother surfaces is less as smooth objects move easily.
The factors that affect friction are as follows:-
- Surface on which the object is moved or the nature of the surface. i.e., rough surface, smooth surface, liquids etc
- The weight of the object or the amount of force on the surface by the object