FIGURE 6-1
-In Figure 6-1, the block of mass m is at rest on an inclined plane that makes an angle θ with the horizontal. The force of static friction f must be such that
A) f mg.
B) f mg cosθ.
C) f mg sinθ.
D) f = mg cosθ.
E) f = mg sinθ.

Question

FIGURE 6-1 
-In Figure 6-1, the block of mass m is at rest on an inclined plane that makes an angle θ with the horizontal. The force of static friction f must be such that
A) f > mg. 
B) f > mg cosθ. 
C) f > mg sinθ. 
D) f = mg cosθ. 
E) f = mg sinθ.

Quizplus · Accepted Answer

The force of static friction must balance the component of gravitational force parallel to the incline, which is mg sinθ, to keep the block at rest.

FIGURE 6-1 -In Figure 6-1, the Block of Mass M Is at M