# Coriolis effect

by pwn01
Tags: coriolis, effect
 P: 221 The Coriolis effect is the effect which drives the Foucault pendulum, and which drives cyclones to be counter-clockwise in the northern hemisphere and clockwise in the southern hemisphere. In particular, the Coriolis force is a "ficticious force" that is due to being in a rotating (accelerating) reference frame (in this case the surface of the spinning Earth). It's proportional to your velocity, but always perpendicular to it. It is also perpendicular to the axis of the spinning object. For all horizontal motion in the northern hemisphere, the Coriolis force is always in the direction 90 degrees to the right of the velocity. The Foucault pendulum knocks down a circle of dominoes in clockwise order for that reason. Mathematically, $\vec{F}_{coriolis} = 2m \;\vec{v}\times \vec{\omega}$ where $\vec{v}$ is your velocity, $\vec{\omega}$ is the angular velocity of the Earth with direction pointing out the north pole, and $m$ is your mass. The "$\times$" is a vector cross product.