# Review of Work, Energy and Power

Physics
Terms

## Terms and Formulae

Terms Terms and Formulae

• ### 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.

• ### Formulas

 Work done by a constant force parallel to displacement W = Fx

 Work done by any constant force W = Fx cosθ

 Work-Energy Theorem W = ΔK

 Formula for average power = Definition of instantaneous power P = Formula for instantaneous power P = Fv cosθ

 Work done by a position-dependent force W = F(x)dx force.

 Definition of potential energy. ΔU = - W

 Gravitational potential energy. UG = mgh

 Statement of conservation of mechanical energy. Δ(U+K) = 0

 Definition of total mechanical energy. U + K = E

 Definition of potential energy given a position-dependent force. ΔU = - F(x)dx