Question

Work is done on a 40 pound baby by his mom as she holds him and walks across the room.
true
false
idk
depends on how good you look with the cup
Duh...

Answer 1

False — if the baby is carried at constant height and moved horizontally, the upward force from the mom is perpendicular to the displacement, so the mechanical work done by that force is zero (W = F·d cos90° = 0).

Caveats: if the baby is lifted/lowered or accelerated (vertical motion or speed changes) then work is done. Also the mom still expends metabolic (chemical) energy in her muscles even when the net mechanical work on the baby is zero.