Calculate the maximum constant speed that a freely falling object reaches when air resistance equals gravitational force.
Last updated: March 26, 2026 | By ForgeCalc Engineering
Sphere: 0.47 | Human belly: 1.0-1.3 | Cube: 1.05
Sea level: 1.225 kg/m³ | 3000m: 0.909 kg/m³
Terminal velocity is the maximum constant speed that a freely falling object eventually reaches when the downward force of gravity is exactly balanced by the upward force of air resistance (drag). At this point, the net force on the object becomes zero, acceleration stops, and the object continues to fall at a steady speed.
When an object begins to fall, it accelerates due to gravity. As its speed increases, the drag force (which increases with the square of velocity) also increases. Eventually, the drag force becomes equal to the gravitational force, at which point the object stops accelerating and maintains a constant velocity. For a human skydiver in a belly-to-earth position, this is typically around 53 m/s (190 km/h or 120 mph).
Terminal velocity depends on several factors: the object's mass (heavier objects have higher terminal velocities), the object's cross-sectional area perpendicular to motion (larger areas create more drag), the drag coefficient (which depends on shape and surface properties), and the density of the fluid through which the object falls. This is why skydivers can increase their terminal velocity by changing body position to reduce drag.
Step-by-step guide:
A skydiver with mass 80 kg adopts a head-down streamlined position to maximize speed. In this position, the projected area is approximately 0.5 m² and the drag coefficient is about 0.7 (more aerodynamic than belly-to-earth).
The skydiver reaches a terminal velocity of approximately 60.5 m/s (218 km/h or 135 mph) in the streamlined position. This is significantly faster than the standard belly-to-earth position (53 m/s) due to reduced drag from both the smaller cross-sectional area and more aerodynamic body orientation. This technique is used in speed skydiving competitions and allows skydivers to catch up to others who deployed earlier.
By changing position, a skydiver alters both projected area (A) and drag coefficient (Cd). A head-down position reduces area and improves aerodynamics, significantly increasing terminal velocity from ~53 m/s to over 90 m/s for experienced skydivers.
Yes, unlike in a vacuum where all objects fall at the same rate. A heavier object (higher m) requires more drag force to balance its weight, which means it must reach a higher speed before drag equals weight. This is why a bowling ball falls faster than a feather.
In a vacuum, there is no fluid (ρ = 0), so there is no drag force. Objects would continue accelerating indefinitely under gravity without ever reaching terminal velocity. This is why a feather and hammer fall at the same rate on the Moon.
At higher altitudes, air density (ρ) decreases. Since drag force depends on density, an object must fall faster to generate enough drag to balance its weight. At 10,000m altitude, terminal velocity is about 15% higher than at sea level.
Yes. As a skydiver descends, air density increases, which increases drag and decreases terminal velocity. Skydivers can also actively change their terminal velocity by adjusting body position, deploying drogue chutes, or changing orientation.
Small raindrops (1mm diameter) have a terminal velocity around 4 m/s, while large raindrops (5mm) fall at about 9 m/s. This is much slower than you might expect, which is why rain doesn't hurt when it lands on you despite falling from great heights.
Drag coefficient is determined experimentally through wind tunnel testing or computational fluid dynamics. It depends on object shape, surface roughness, and Reynolds number. Streamlined shapes have lower Cd values (0.04 for airfoils) while bluff bodies have higher values (1.0+ for flat plates).
Felix Baumgartner reached 373 m/s (1,357 km/h or 843 mph) during his stratospheric jump in 2012, briefly exceeding the speed of sound. This was possible due to extremely low air density at high altitude (39 km). His terminal velocity decreased as he descended into denser air.