Question

If a weight lifter is holding barbells above his head, what does he have to do to perform work?
Group of answer choices

lower barbells

step forward

stand still

step backwards

Answer 1

Lower the barbells.

Explanation: In physics, work = force · displacement. While holding still there's no displacement so no work. Stepping forward or back moves horizontally, perpendicular to the upward force, so the upward force does no work. Lowering the barbells produces a vertical displacement, so the lifter does (nonzero, in fact negative) work on the weights.