Aerodynamic Drag

Aerodynamic drag on a roller coaster can be a major factor in accurately determining its velocity, particularly at high speeds. It is modeled as follows.

$$F_{f_{a}} = \frac{1}{2} \rho A_{f}C_{d} v^{2}$$

Where $\rho$ is the density of air, $A_{f}$ is the frontal area, $C_{d}$ is the drag coefficient, and $v$ is the forward velocity of the car. This, of course, assumes the coaster is moving through still air....