Drag Force Equation

Reference from the original Physics I textbook.

Quadratic drag magnitude: $F_{drag} = \frac{1}{2} ρ v^{2} A C_{D}$ . The drag vector opposes velocity relative to the fluid.

${\vec{F}}_{d r a g} = Drag Force (N)$
$ρ = Density of Air \approx 1.2 {kg/m}^{3} under normal conditions$
$\vec{v} = Velocity (m/s)$
$A = {Cross-sectional Area (m}^{2})$
$C_{D} = Drag coefficient (unitless)$

$[\begin{aligned} 1 Newton & = 1 kg \cdot m / s^{2} \end{aligned}]$

Related Glossary Terms

Drag Force, Velocity↗

Index

Chapter 2 - Force Analysis

Chapter 2 - FFR - Work

Reviewed physics notes (1)

These corrections keep the original lesson’s purpose while fixing errors in the source edition.

The original uses a vector squared and omits its direction. — Reference 1

About this edition and its source ↗

Glossary and deeper reading · 2 refreshers

These editorial refreshers supplement the reading. Definitions and examples are added guidance; original source wording and recorded answers remain in their original context.

Drag
Drag is a force from a fluid that opposes an object’s motion relative to that fluid. Its dependence on speed, shape, and fluid properties varies with the physical regime. For example, a parachute increases air drag by presenting a large area to the moving air.
Velocity
Velocity describes how position changes with time and includes direction. Instantaneous velocity describes one moment, while average velocity is displacement divided by elapsed time. For example, a car turning a corner can change velocity while maintaining the same speed.
Read more: Variables of motion →

Drag Force Equation

Drag

Velocity

Help us improve Omniguides