moment of inertia

In physics, the sum of all the point masses of a rotating object multiplied by the squares of their respective distances from the axis of rotation.

In linear dynamics, Newton's second law of motion states that the force F on a moving object equals the products of its mass m and acceleration a (F = ma); the analogous equation in rotational dynamics is T = Iα, where T is the torque (the turning effect of a force) that causes an angular acceleration α and I is the moment of inertia. For a given object, I depends on its shape and the position of its axis of rotation.