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

The friction force acting on the brick, along the incline, is opposing the motion and therefore acts in the direction opposite to the motion. Since the brick is at rest, the friction force must be equal and opposite to the force of gravity acting on the brick. Therefore, the friction force is less than the weight of the brick. Choice D is the best choice.

A Brick Is Resting on a Rough Incline as Shown