# Physics equations/Equations/Rotational and linear motion analogy

The following table refers to rotation of a rigid body about a fixed axis: is arclength, is the distance from the axis to any point, and is the tangential acceleration, which is the component of the acceleration that is *parallel* to the motion. In contrast, the centripetal acceleration, , is *perpendicular* to the motion. The component of the force parallel to the motion, or equivalently, *perpendicular*, to the line connecting the point of application to the axis is . The sum is over particles or points of application.

Linear motion | Rotational motion | Defining equation |
---|---|---|

Displacement = | Angular displacement = | |

Velocity = | Angular velocity = | |

Acceleration = | Angular acceleration = | |

Mass = | Moment of Inertia = | |

Force = | Torque = | |

Momentum= | Angular momentum= | |

Kinetic energy = | Kinetic energy = |