Jill is pushing a box across the floor. which represents the upward force perpendicular to the floor?

a. fp
b. ff
c. fn
d. fg

The answer would be FN, because upward force would be natural force.

Hope this helps.

When Jill is pushing a box across the floor,  the force upward is considered as natural force, which is a force that is not controlled by human. (the human only controlled the movement to the front or to the back)
From the option above, the one that represents natural force in physics is: C. FN

Ifound this on google i hope it you