How to use: A moment is a force times the distance from the pivot to
where you push or pull, so moving something further out makes it stronger without
needing a bigger force. Drag the amber load or the effort arrow
along the beam, or use the sliders for exact values. The beam tips towards whichever
side has the larger moment, and turns level when the two match. The four buttons set
up real levers: a seesaw, a wheelbarrow, your elbow and a crowbar. Compare
Advantage across them, then watch Work in / out. On a level beam the
two numbers are equal, because a lever never saves work — it only trades distance
against force. Tip the beam off level and they part company: the surplus is what
would go into swinging the beam faster.
Notice: the wheelbarrow lifts 500 N with 200 N and the crowbar does far better
again, yet in each case the work you put in exactly matches the work you get out. A
lever trades a long push for a short lift, never less work — which is why your bicep
has such a bad deal and still ends up taking the load.