Answer the following with reference to static and kinetic friction between two solid surfaces:
a. (i) Define static friction and kinetic friction.
b. (ii) Explain with a microscopic reason why the coefficient of static friction is generally greater than the coefficient of kinetic friction.
c. (iii) Using the difference between the two types of friction, explain how a person is able to walk forward without slipping and why an unexpected thin layer of oil on the road surface can cause skidding.