Polly is pushing a box 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?

The answer is -30 N

The explanation:

- to make the box move. so,the horizontal force must be greater than the frictional force.

-and when the horizontal force applied is 30 N. So, the box will remain stationary if the frictional force is equal in magnitude but opposite in direction to the horizontal force. means frictional force = -30 N

This is also being indicate that vertical force due to gravity is equivalent to the normal force when gravity force = 8 N and normal force =8 , meaning the box does not move vertically.

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1.43 x 10^-11 j the guy commented the awnser just making sure u see it .