# Terminal Speed

The speed obtained in free fall when the upward force of air resistance is equal to the downward force of gravity.

- Balancing the force due to air resistance,
- this gives
- this can then be rearranged to give the terminal speed,
*v*
- where
*F*= aerodynamic drag force [N]*C*= drag coefficient_{d}*A*= frontal area [m^{2}]*ρ*= density of fluid [kgm^{-3}]*v*= velocity of object relative to fluid [ms^{-1}]*m*= mass of object [kg]*g*= standard acceleration due to gravity [ms^{-2}]
F and the downward force of gravity, _{A}F _{g} |

**See also: **Acceleration, Buoyant Force, Drag Coefficient, Standard Acceleration due to Gravity, Velocity.