Degrees of freedom (mechanics)

Number of independent parameters needed to define the state of a mechanical system

In physics, the number of degrees of freedom (DOF) of a mechanical system is the number of independent parameters required to completely specify its configuration or state. That number is an important property in the analysis of systems of bodies in mechanical engineering, structural engineering, aerospace engineering, robotics, and other fields. As an example, the position of a train has one degree of freedom because it can be completely specified by a single value expressing the locomotive's distance along the track.

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