Moment of Inertia |
1. Introduction
The angular acceleration of a body subjected to a torque depends upon it's moment of
inertia. This is a measure of the distribution of the mass within the body.
Where a body is pivoted about a fixed point it is the moment of inertia about this
fixed point that is the appropriate value. Where a body is free to move in an unconstrained
manner, then the linear motion (translation) of the centre of mass is considered and the
rotation about the centre of mass - so in this case it is the moment of inertia about the
centre of mass that is required.
2. Derivation
The section below shows in general terms how the moment of inertia is derived.
3. Two Theorems
David J Grieve. Modified: 10th March 2011, original: 15th November 2001.