Work is path-dependent only with friction
- 01
The tempting model
Assuming gravitational work depends on the route taken.
- 02
Why it feels right
A longer path feels like it should cost more energy.
- 03
Where it breaks · how to catch it
You integrated gravity along a winding path expecting a path-dependent answer.
- 04
The correct model
Conservative forces (gravity, spring) depend only on endpoints. Only non-conservative forces like friction make work path-dependent.
- 05
Repair · see it, then test it
worked example Work by gravity moving a mass up two different frictionless ramps to the same height?
Tempting move
Different — the ramps differ.
Correct move
Same: −mgh either way (endpoints only).
Test the repair EN-04 · transferMake a fresh prediction before referring to the worked example.
Then practise it on the ladder
R17Endpoint work by gravityadds: Conservative work depends on endpoints, not the path.