# Precession

A falling object that rotates will fall “sideways” rather than straight down in the direction of gravity. This causes a sideways motion that becomes a sideways (horizontal) rotation, called precession. The precession angular speed is:

$$\omega_\text{precession}=\frac{wr}{L_\text{spin}}$$

where $w$ is the weight, $r$ the precession circle’s radius and \$L_\text{spin} the angular momentum due to the object’s spin about its own tilted axis.