Work is path-dependent only with friction

  1. 01

    The tempting model

    Assuming gravitational work depends on the route taken.

  2. 02

    Why it feels right

    A longer path feels like it should cost more energy.

  3. 03

    Where it breaks · how to catch it

    You integrated gravity along a winding path expecting a path-dependent answer.

  4. 04

    The correct model

    Conservative forces (gravity, spring) depend only on endpoints. Only non-conservative forces like friction make work path-dependent.

  5. 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 · transfer
    A climber reaches the same ledge by a steep route and a winding route. What is true of the work done by gravity?

    Make a fresh prediction before referring to the worked example.