Conservative force

Conservative forces are those that possess certain properties:[1]

* The work it does on a particle is independent of its trajectory.
* The work done on a particle that moves along a closed trajectory (where the initial and final positions are the same, or di = df) = 0) is zero.
* The force can be written as the negative of the gradient of a potential energy function, i.e. .
* The curl of the force,  is zero,

When the only forces present in a system are conservative, energy is conserved.

Examples of conservative forces include:

* Gravitational force
* Force performed by a spring

Friction is an example of a non-conservative force:

## References[edit]

1. ↑ Serway and Beichner, Physics for Scientists and Engineers, Fifth Edition