Question

The frictional force is directly proportional to the ____________

(a) Applied load

(b) Type of surface used

(c) The normal force

(d) The horizontal load

This question was addressed to me in an international level competition.

I want to ask this question from Characteristics of Dry Friction in portion Friction of Engineering Mechanics

Answer 1

The correct option is (c) The normal force

Explanation: The frictional force is directly proportional to the vertical force that is being applied normal to the surface of the body. The force of friction is not dependent on the type of the surface. Thus the only thing the frictional force does depend is the normal force.