A 100 N push lifts a 400 N load.

Each weight turns the bar: force × distance from the pivot.

Slide 100 N further out, and its turn grows.

At 1 m: 100 × 1 = 400 × 0.25. Balanced.

Archimedes proved this rule.

But you pay in distance.

Push the long end down 0.20 m; the load rises 0.05 m.

Work is force × distance.

100 N × 0.20 m = 20 J. 400 N × 0.05 m = 20 J.

The same work. The lever makes no energy.

Move the pivot closer to the load.

17 N lifts 400 N, if you push 24 times as far.

A lever trades force for distance. Never energy.