Question

Which statements describe a situation in which work is being done? Select three options.

A mover carries a box up a flight of stairs.
A mover holds a box with an upward force while moving it horizontally.
Wind blows against a steel table anchored to the ground.
Wind blows a pool chair across the yard.
A weightlifter lifts a barbell off the ground.
A weightlifter holds a barbell above the head.

Answer 1

Work = force · displacement (only the component of force along the displacement does work). So pick cases with a force and a displacement along that force:

- A mover carries a box up a flight of stairs. (Yes — upward force and upward displacement.)
- Wind blows a pool chair across the yard. (Yes — wind force and displacement in the same direction.)
- A weightlifter lifts a barbell off the ground. (Yes — upward force and upward displacement.)

So: A, D, and E.