Poinsot's central axis

Poinsot's central axis

[¦pwän·sōz ¦sen·trəl ′ak·səs]
(mechanics)
A line through a rigid body which is parallel to the vector sumFof a system of forces acting on the body, and which is located so that the system of forces is equivalent to the forceFapplied anywhere along the line, plus a couple whose torque is equal to the component of the total torqueTexerted by the system in the directionF.