Question

What force is pushing a crate in the floor?

Answer 1

friction

Push an empty box on a smooth floor and then let go. It moves 1 or 2 meters and then stops. The force that stops the box is called force of friction. It is a force that opposes any motion!

Answer 2

friction force is actually opposing the motion of crate but the external provided force is the one which is pushing the crate.

hope it helps you.