A friction force
A) is a contact force that acts parallel to the contact surfaces.
B) is a normal force between contact surfaces.
C) is a scalar quantity since it can act in any direction along a surface.
D) does not depend on the nature of the surfaces.

Question

Quizplus · Accepted Answer

A friction force acts parallel to the contact surfaces and opposes the relative motion of the surfaces. It is a vector quantity and its magnitude depends on the nature of the surfaces in contact and the force pushing them together.

A Friction Force