DAVID G. SIMPSON 


ROUTH'S RULERouth's rule is a mnemonic formula for finding the moment of inertia of a symmetrical solid. The rule works for a circular or elliptical cylinder rotated about the cylinder axis, or for a circular or elliptical disk about any of the axes of symmetry.Routh's rule states that the moment of inertia I of a body of mass M about an axis is given by [1] where the denominator is 3 for a rectangular body, 4 for a elliptical body, or 5 for an ellipsoidal body. ExampleFor example, consider the moment of inertia of a solid uniform right circular cylinder of radius R rotated about the axis of the cylinder. Then the numerator in Routh's rule is R^{2} + R^{2} = 2R^{2}, while the denominator is 4 (a circle is a special case of ellipse), so
See AlsoReferences^{[1]} H.J. Gray and A. Isaacs (eds.). A New Dictionary of Physics. Longman, London, 1975.
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