Free Fall Air Resistance Calculator

Free Fall With Air Resistance

Real objects experience drag that opposes motion. As speed increases, drag grows until it balances weight. At that point acceleration stops and the object reaches terminal velocity—the constant maximum speed during a long fall.

Terminal Velocity Formula

$$v_t = \sqrt{\frac{2mg}{\rho C_d A}}$$

$m$ is mass in kg, $g$ is gravity in m/s², $\rho$ is air density in kg/m³, $C_d$ is the drag coefficient, and $A$ is cross-sectional area in m². A 80 kg person with $A = 0.7$ m², $C_d = 1.2$, and $\rho = 1.225$ kg/m³ reaches about 39 m/s (140 km/h).

Factors That Affect Terminal Speed

Heavier, compact objects fall faster because weight grows with mass while drag depends on area. Lower air density (high altitude) increases terminal velocity. Streamlined shapes with lower $C_d$ also fall faster.

Related tools: Free Fall Calculator and G-Force Calculator.

Frequently Asked Questions

What is terminal velocity?

Terminal velocity is the constant speed reached when air drag equals gravitational weight. Beyond this speed, net force is zero and acceleration stops.

What drag coefficient should I use?

Approximate values: sphere ≈ 0.5, skydiver belly-down ≈ 1.0–1.3, streamlined body ≈ 0.04–0.1. Use published values for your shape when possible.

What air density should I use?

Sea level standard air is about 1.225 kg/m³ at 15°C. Density decreases with altitude and increases in cold air.

Does mass affect terminal velocity?

Yes. Heavier objects with the same size and shape have higher terminal velocity because weight increases with mass but drag does not.

Is this the same as vacuum free fall?

No. Vacuum free fall has no speed limit and keeps accelerating. With air resistance, speed plateaus at terminal velocity.

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Free Fall Air Resistance Calculator

Free Fall With Air Resistance

Terminal Velocity Formula

Factors That Affect Terminal Speed

Frequently Asked Questions

Related Tools

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