The Moment of Inertia is often given the symbol * I*. It is the rotational analogue of mass. In Newtonian physics the acceleration of a body is inversely proportional to mass. In Newtonian rotational physics angular acceleration is inversely proportional to the moment of inertia of a body. You can think of the moment of inertia as the ability to resist a twisting force or torque.

For rotation about a fixed point, the moment of inertia of a body * I* is given by the sum of all the constituent particles masses

The angular momentum of a solid object is just * Iω* where

**Some moments of inertia for various shapes/objects**

For a uniform disk of radius * r* and total mass

For a solid sphere * I=2/5 m r^{2}*.

A point particle of mass * m* in orbit at a distance

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