Conservative force  -  Any force which conserves mechanical energy, as opposed to a nonconservative force. See statement of conservation of mechanical energy.

Conservative System  -  A system in which energy is conserved.

Energy  -  The ability to do work.

Kinetic Energy  -  The energy of motion.

Nonconservative Force  -  Any force which does not conserve mechanical energy, as opposed to a conservative force.

Path independence  -  Property of conservative forces which states that the work done on any path between two given points is the same.

Potential energy  -  The energy of configuration of a conservative system. For formulae, see Definition of potential energy, gravitational potential energy, and Definition of potential energy given a position-dependent force.

Total mechanical energy  -  The sum of the kinetic and potential energy of a conservative system. See definition of total mechanical energy.

Work  -  A force applied over a distance. For formulas, see work done by a constant force parallel to displacement and work done by any constant force, and work done by a position-dependent force.

Joule  -  The units of work, equivalent to a Newton-meter. Also units of energy.

Power  -  Work done per unit time. For formulas, see Formula for average power, Definition of instantaneous power, and formula for instantaneous power.

Watt  -  Unit of power; equal to joule/second.