Polly is pushing a box to the right across the floor with a force of 30 N. The force of gravity is 8 N, and the normal force is 8 N. Which value could describe the force of friction if Polly could not move the box?

A. [tex]$\leftarrow 30 N$[/tex]
B. [tex]$\leftarrow 8 N$[/tex]
C. [tex]$\rightarrow 8 N$[/tex]
D. [tex]$\rightarrow 30 N$[/tex]



Answer :

Sure, let's work through this problem step-by-step to find the force of friction:

1. Understanding the forces involved:
- Polly is pushing the box to the right with a force of 30 N.
- The force of gravity acting downward on the box is 8 N.
- The normal force, which is the force exerted by the floor on the box and acts upward, is also 8 N.
- The box does not move.

2. Key concept:
- Since the box does not move, this means that the force Polly applies to the box is exactly countered by the force of friction.

3. Analyzing the situation:
- Polly applies a force of 30 N to the right, but the box does not move. This non-movement indicates that there is a frictional force of equal magnitude acting in the opposite direction.

4. Determining the force of friction:
- For Polly's applied force (30 N) to be countered exactly, the frictional force must also be 30 N, but directed to the left to balance the applied force.

5. Concluding the value of the frictional force:
- The value that describes the force of friction in this scenario is 30 N, directed to the left.

So, the correct answer is that the force of friction could be [tex]\( \leftarrow 30 N \)[/tex].