Flywheels resist changes in rotational speed by their moment of inertia. It is a measure of rotational inertia. That modification improved roll rate by reducing rotational inertia. Volumetric objects behave like real physical objects with mass, inertia and velocity. Particularly troubling was the yaw instability in certain regimes of flight which produced inertia coupling. Honda increased the diameter of the flywheel for more inertia. It was a step toward the modern ideas of inertia and momentum. Reversed&colon; Inertia, fixity, stagnation, permanence. This classification depends on the relative magnitudes of the principal moments of inertia. The covariance matrix is related to the moment of inertia tensor for multivariate distributions. The whole locomotive tends to move under the influence of unbalanced inertia forces. This conception of motion is consistent with Newton's first law of motion, inertia. In a sense, thermal diffusivity is the measure of thermal inertia. Hele-Shaw flow is an example of a geometry for which inertia forces are negligible. This list of moment of inertia tensors is given for principal axes of each object.