Question

The wood block in figure 5.22 is at rest on a wood ramp. In which direction is the static force on block 1?

A up the ramp
B down the ramp
C the friction force is 0
D There's not enough information to tell

Answer 1

The static force on block 1 is in the direction B, down the ramp.

Step-by-step explanation:

In this scenario, the wood block is at rest on the wood ramp, indicating an equilibrium state where the net force is zero. Considering the forces acting on block 1, gravity pulls it downward (denoted as mg), and the normal force perpendicular to the ramp opposes this gravitational force. However, the static friction force counters the tendency of the block to slide down the ramp. The direction of the static force, therefore, opposes the component of the gravitational force that tends to move the block down the ramp.

The static friction force, which prevents the block from sliding, acts opposite to the direction of impending motion. In this case, since the block is inclined on the ramp, the component of gravity parallel to the ramp tends to pull the block down.

Thus, the static force on block 1 acts in the direction down the ramp (option B). This direction is opposite to the component of the gravitational force that's trying to propel the block downward, maintaining the block's static equilibrium on the ramp. Therefore, the correct answer is B, down the ramp.