(German, Trdgheitsmoment; French, Moment d'enerlie, or Moment de giration.)

The moment of inertia, sometimes called the moment of gyration, is the formula representing the inactivity (or state of rest) of any body rotating around any axis. The reason of the connection of this formula with the calculation of strains and the manner of obtaining it cannot be gone into here, as it would be quite beyond the scope of these articles. The moment of 1 If line X-Y is inside of (bisects) figure, take sum of products on one side only and deduct sum of products on other side.

Moment of Inertia. (See Table I.) inertia of any body or figure is the sum of the products of each particle of the body or figure multiplied by the square of its distance from the axis around which the body or figure is rotating.

A table of moments of inertia, of various sections, will be given later on and will be all the student will need for practical purposes.