\[F_d = \frac{1}{2}\rho v^2 C_d A\]
Variables
Fddrag force (N)
rhofluid density (kg/m³)
vrelative velocity (m/s)
Cddrag coefficient
Areference area (m²)
Description
What is this formula?
The drag force equation calculates the resistive force exerted by a fluid on an object moving through it. The force depends on fluid density, object speed, drag coefficient, and reference area.
When to use it
Use this formula when analyzing aerodynamics, vehicle resistance, aircraft performance, fluid flow, or moving objects in air or water.
Example
An object moves through air at 20 m/s with drag coefficient 0.8 and frontal area 0.5 m². Air density is 1.225 kg/m³.
Data:
rho = 1.225 kg/m³
v = 20 m/s
Cd = 0.8
A = 0.5 m²
Formula:
Fd = 0.5*rho*v²*Cd*A
Substitution:
Fd = 0.5*1.225*20²*0.8*0.5
Result:
Fd = 98 N
Applications
Aerodynamics, automotive engineering, aerospace engineering, hydrodynamics, sports engineering, and fluid mechanics.