Question

Frictional force between two surfaces always acts
A) parallel to the surface
B) perpendicular to the surface
C) in any direction
D) none of the above

Answer 1

Answer:

(A) parrelel to the surface

Answer 2

The dependence of friction on materials and the normal force. The direction of friction is always opposite that of motion, parallel to the surface between objects, and perpendicular to the normal force.