Which is NOT an example of work? pushing a box across the floor

trying to push a rock that never moves

picking up a box off the floor

raising a barbell over your head

trying to push a rock that never moves

Explanation:

let me try my best to break the concepts down for you.

the definition of work done is

work done by a constant force on an object is the product of the force and the distance moved by the object in the direction of the force.

this means that when you apply a force, it must move.

basically it is like holding a book in your hands and not moving, are you fighting the gravitational force?

when you push a box, it definitely moves in the direction you push right?

when you raise the barbel, you are applying a upward force, and barbel us moving upwards, so work is done

hope it helps, if not please report it so that someone else gets to try it

b.a device that inputs heat into a cool object