Learn the definition, formulation and applications of radius of gyration , a measure of the distribution of mass or area around an axis. Find out how it is used in physics, engineering, polymer science and geographical data analysis. Radius of Gyration, or the radius of a body, is always centered on its rotational axis . It is a geometric characteristic of a rigid body and is described as the distance between the axis of the body to the point where the body's moment of inertia is the same as the body's total moment of inertia. Learn what radius of gyration is, how to calculate it, and why it is useful in physics and engineering. See the formula, the unit, and two example problems with solutions. Learn about the radius of gyration in this article, its definition, formula, applications like determine the pressure exerted by a body, solved examples