Applications
Poles and polars were defined by Joseph Diaz Gergonne and play an important role in his solution of the problem of Apollonius.
In planar dynamics a pole is a center of rotation, the polar is the force line of action and the conic is the mass-inertia matrix. The pole-polar relationship is used to define the center of percussion of a planar rigid body. If the pole is the hinge point, then the polar is the percussion line of action as described in planar screw theory.
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