Science
Quadratic fluid drag
Estimate drag and the power needed to overcome it at a fixed relative speed.
Calculators / Science / Terminal speed with quadratic drag
Terminal speed with quadratic drag calculator
Estimate the speed at which quadratic drag balances an object’s weight.
On this page
Terminal speed42.78m/s
Balancing drag force784.53N
Calculator controls
How to calculate
Estimate the speed at which quadratic drag balances an object’s weight.
Terminal speed =
sqrt(2*m*g/(rho*Cd*A)) m/sBalancing drag force =
m*g NWorked example
- Object mass (kg): 80
- Gravity (m/s²): 9.80665
- Fluid density (kg/m³): 1.225
- Drag coefficient: 1
- Frontal area (m²): 0.7
- Terminal speed: 42.78 m/s
- Balancing drag force: 784.53 N
Assumptions and limits
This is an ideal educational model. Enter quantities in the stated SI units; it does not certify equipment safety or real operating limits. Drag coefficient, area and fluid density are constant; buoyancy and changing altitude are ignored.
Results are rounded for display; calculations use unrounded values. Read our calculation methodology.
Understanding the result
Estimate the speed at which quadratic drag balances an object’s weight. Choose drag coefficient and frontal area for the actual orientation. This is not a parachute or fall-safety calculation.
When this tool is useful
Choose drag coefficient and frontal area for the actual orientation. This is not a parachute or fall-safety calculation.
Understanding your inputs
| Input | Example |
|---|---|
Object mass (kg) m | 80 |
Gravity (m/s²) g | 9.80665 |
Fluid density (kg/m³) rho | 1.225 |
Drag coefficient Cd | 1 |
Frontal area (m²) A | 0.7 |
Frequently asked questions
Which assumptions matter for this result?
This is an ideal educational model. Enter quantities in the stated SI units; it does not certify equipment safety or real operating limits. Drag coefficient, area and fluid density are constant; buoyancy and changing altitude are ignored.
How can I check the worked example?
Use the displayed example inputs in the stated formula. Keep each quantity in its labelled unit and compare the unrounded result before applying display rounding.