Mechanical

Mass Moment of Inertia (Rotational Inertia)

Definition

A measure of an object's resistance to angular acceleration, analogous to mass for linear motion. Depends on mass distribution relative to the rotation axis. Units: kg·m², lb·ft².

Practical Note

I = m×r² for a point mass at radius r. Solid cylinder: I = ½mr². Hollow cylinder: I = mr². Mass farther from axis increases I dramatically (r² relationship).

Related Calculators

Related Terms