A brick is resting on a rough incline as shown in the figure.The friction force acting on the brick,along the incline,is
A) zero.
B) equal to the weight of the brick.
C) greater than the weight of the brick.
D) less than the weight of the brick.

Question

A brick is resting on a rough incline as shown in the figure.The friction force acting on the brick,along the incline,is 
A) zero. 
B) equal to the weight of the brick. 
C) greater than the weight of the brick. 
D) less than the weight of the brick.

Quizplus · Accepted Answer

Since the brick is resting on the incline, it means that the gravitational force acting on the brick is balanced by the normal force perpendicular to the incline. However, there is still a component of the gravitational force acting down the incline. The friction force acts to oppose this component of the gravitational force, so it will be less than the weight of the brick. Therefore, choice D is the best answer.

A Brick Is Resting on a Rough Incline as Shown