Question

Why do smooth surface offer less friction in comparison to rough s
urface?

Answer 1

Smooth surface cause less friction because it have less area exposed to the substance reacting with it.

Answer 2

a rough surface increases friction whereas smooth surface reduces friction because friction is caused due to the roughness and irregularities of the surface of the two objects in contact.. when rough surface brush against each other, their irregularities come in contact.. many of these irregularities interlock and thus increases friction between the rough surface