Moment of inertia help

1. Feb 1, 2012

michaelknight

what is a moment of inertia? I know it's used for angular mechanics (like angular velocity and stuff like that), but what is a moment of inertia? A good definition with some examples would help tremendously. Thank you much in advance :)

2. Feb 1, 2012

tiny-tim

hi michael!

just as the mass (or inertia) of a body is the ratio between any force on it and its (linear) acceleration,

so the moment of inertia of a body is the ratio between the moment of force (also called the torque) on it and its angular acceleration

in other words: mass (or inertia) tells you how difficult it is to push, while moment of inertia tells you how difficult it is to turn

(for examples, see the pf library or wikipedia)

Last edited: Feb 1, 2012