Laws of Friction

Introduction:

Smooth surfaces are defined by the property that when they are in contact, the surfaces is always perpendicular to their common tangent plane. It can, however, be verified experimentally that no surfaces that are perfectly smooth and that whenever there is a tendency for two bodies which are in contact to move relative to each other, a force known as the force of friction tends to prevent the relative motion. The mathematical discussion of the force of friction that depends on certain assumptions which are embodied in the so called laws of friction and are found to be in close agreement with experiments. I like to share this Equation for Impulse with you all through my article.


Co-efficient friction:


Law 1

When two bodies are in the contact the direction of the forces of Friction on one of them at it's point of contact, is opposite to the direction in which the point of contact tends to move relative to the other.

Law 2

If the bodies are in the equilibrium, the force of Friction is just sufficient to prevent friction and may therefore be determined by applying the conditions of equilibrium of all the forces acting on the body.

Law 3

The ratio of the reducing friction to the Normal reaction between two surfaces depends on the substances of which the surfaces are composed and not on the magnitude of the Normal reaction. This ratio is usually denoted by .

Thus if the Normal reaction is R, the limiting friction is

For given materials polished to the same standard are found to be constant and independent of R. is called The Coefficient of friction. Please express your views of this topic Definition of Electromagnet by commenting on blog.


Basic Laws of friction:


Law 4

The amount of reducing friction is independent of the area of contact between the two surfaces and of the shape of the surfaces, provided that the Normal reaction is unaltered.

Law 5

When motion takes place in the direction of friction is opposite to the direction of relative motion and independent of velocity. The magnitude of the force of friction is a constant ratio to the Normal reaction but this ratio may be slightly less than when the body is just on the point of moving.