## Force vs. Power

The concepts of **force** and **power** seem to convey similar meanings and are often confused for each other. But in physics, they are not interchangeable. **Force** is the fundamental result of an interaction between two objects, while **power** is an expression of energy consumed over time (work), of which force is an element. Force and power can both be described and measured, but a force is an actual physical phenomenon, and power in itself is not.

### Comparison chart

Force versus Power comparison chartForce | Power | |
---|---|---|

Definition | A push or a pull resulting from an interaction between objects. | Power is the rate at which work is done, or energy is transmitted. |

Unit | newton | watt = joules/second |

Symbol | F | P |

Named After | Isaac Newton | James Watt |

Derivations from other quantities | F = m a (force = mass multiplied by acceleration) | P = w/t (power = work divided by time) |

Relation to “Work” | Force applied over a distance creates work. | Rate at which work is performed. |

Everyday Example | Gravity, friction, magnetism. | Horsepower (1 horsepower = 750 Watts). |

### Basic Concept

A force can only occur when objects are interacting. Whenever objects interact, they push or pull one another, whether through direct contact or at-a-distance contact. Examples of direct contact forces include the friction of car tires on a road, or the air resistance on a moving car. At-a-distance interaction occurs through forces like gravity and magnetism. Force is a fundamental expression of physical occurrences, as are time and distance.

Power is defined as the amount of energy consumed per unit of time. Another way to put this is: the rate at which “work” is done. Work occurs when there is force causing movement of an object. For example, a person pressing against a brick wall is consuming energy, but no work is being done and no power created because the wall does not move. But if a person pushes on a table and moves it, then there is work. Power expresses how quickly that work is done. So, force is one element of the power equation, along with other basic elements like distance and time.

### Formulae

Force is calculated as a product of mass and gravitational acceleration, and is usually denoted as