Question

why rough surface cause more friction

Answer 1

Heya user!
It is because the rough surface produce static friction. A friction in which the surfaces of the body is at rest relative to each other. Hope u find it helpful....

Answer 2

A pair of rough surfaces will have more friction than a pair of smooth surfaces, because the “peaks” of one surface can fall into the “valleys” of the other, meaning that to keep moving either something needs to break, or the surfaces would need to push apart briefly.