Physics
The drag force itself
Quadratic drag, the force that grows until it matches weight.
The Formula
F = 0.5 x rho x v^2 x Cd x A
Quadratic drag, the force that grows until it matches weight.
| Symbol | Meaning | Unit | Notes |
|---|---|---|---|
| F | Drag force | newtons | The upward force from the air. |
| rho | Air density | kg per cubic metre | The density of the fluid. |
| v | Speed | metres per second | The current falling speed. |
| A | Presented area | square metres | The area facing the flow. |
What Each Symbol Means
Fnewtons
Drag force
The upward force from the air.
rhokg per cubic metre
Air density
The density of the fluid.
vmetres per second
Speed
The current falling speed.
Asquare metres
Presented area
The area facing the flow.
See It Worked With Real Numbers
A formula on its own does not tell you which number goes where. The how to calculate terminal velocity page applies this equation to a concrete case, shows every intermediate step, and names the mistakes that produce a wrong answer even when the algebra is right.
Where This Formula Appears
This equation is the working core of How To Calculate Terminal Velocity, filed under Science. Every number the guide produces comes from substituting into this one line.