A shoe on an inclined surface barely remains at rest when friction equals the
A)weight mg of the shoe.
B)component of mg perpendicular to the surface.
C)component of mg parallel to the surface.
D)none of the above

Question

Quizplus · Accepted Answer

The component of the gravitational force (mg) parallel to the surface is what tries to pull the shoe down the incline. Friction acts to counter this force, and when the shoe barely remains at rest, the frictional force equals this parallel component of the gravitational force, not the total weight or the perpendicular component.

A Shoe on an Inclined Surface Barely Remains at Rest