Question

define friction what are its coeses

Answer 1

Friction is a type of contact force...This Force comes into play only if there is a contact between the two bodies or objects or surfaces...This force Opposes the motion of object...

Which means If body tend to move in farward direction...this force starts opposing the body in opposite Direction..

So Friction force always acts in the opposite direction of motion...

Cause Of Friction -> Friction causes due to irregularities between the Two surfaces and How strongly one surface hold the other surface i.e Interlocking between the two surfaces...

Regular Surfaces are smooth and interlocking between these surfaces is not much strong
which results lesser friction force between the same...

Whereas Irregular surfaces are Rough and interlocking is strong between them which results the stronger frictional force between the surfaces..