What is friction? Define coefficient of static friction with necessary formulae

Define coefficient of Kinetic friction. Give the necessary formulae.

What is friction? Define coefficient of static friction and coefficient of kinetic friction. Give the necessary formula for each.

Explain static friction

Coefficient of static friction does not depend upon

Friction is a necessary evil.

Define friction.

Define friction.

State the laws of static friction.

Maximum value of static friction is .

A 20 kg metal block is placed on a horizontal surface. The block just begins to slide when horizontal force of 100N is applied to it . Calculate the coefficient of static friction . If coefficient of kinetic friction is 0.4 then find minimum force to maintain its uniform motion.