What cause friction?

Answer 1

The causes of the resistive force of friction are

1.molecular adhesion

2.surface roughness

3.the plowing effect.

Adhesion is the molecular force resulting when two materials are brought into close contact with each other. Trying to slide objects against each other requires breaking these adhesive bonds. For years, scientists thought that friction was caused by surface roughness, but recent studies have shown that it is actually a result of adhesive forces between the materials.

But surface roughness is a factor when the materials are rough enough to cause serious abrasion. This is called the sandpaper effect.

When one or more of the materials is relatively soft, much of the resistance to movement is caused by deformations of the objects or by a plowing effect.

Answer 2

Friction is caused by the interaction between two surfaces as they rub against each other. Microscopic imperfections on the surfaces can catch on each other, resisting motion and causing heat to be generated. The amount of friction depends on factors such as the roughness of the surfaces and the force pressing them together.