Friction

Question 1

Describe the characteristics of friction

Answer 1

1. Friction is irrelevant of relative speeds of two surfaces which are in contact
2. Friction opposes relative motion between 2 surfaces in contact.
3. No sliding occurs when friction<=uR
4. Sliding occurs when f=uR,this is said to be limiting equilibrium
5. Friction is found by the product of the roughness of the surface and the normal contact force.

Question 2

What is the formula for the angle of friction?

Answer 2

It is that tan theta=u.The angle for which a block is about to slide down a slope.