Quadratic Drag Force

Fd = (1/2)·ρ·Cd·A·v^2

What it says

The resistive force on a body moving fast through a fluid, scaling with fluid density, drag coefficient, frontal area, and the square of speed.

Symbol	Quantity	Dimension
`Fd`	Drag force (N)	`M L T^-2`
`ρ`	Fluid density (kg/m^3)	`M L^-3`
`Cd`	Drag coefficient (dimensionless)	`1`
`A`	Frontal area (m^2)	`L^2`
`v`	Speed relative to fluid (m/s)	`L T^-1`

Enter what you know. No account needed.

ρ — Fluid density (kg/m^3)Cd — Drag coefficient (dimensionless)A — Frontal area (m^2)v — Speed relative to fluid (m/s)