The terminal velocity is affected by the amount of air resistance encountered during the descent. A person who is spread-eagled will move slower than a person falling feet first. Terminal velocity may reach over 70 meters per second in a skydiver.
terminal velocity in meters per second =
= SQRT((mass in kilograms) * (gravity in m per second square) / (constant))
|
Fall Position
|
Constant
|
|
spread-eagled
|
0.515
|
|
feet first
|
0.067
|
velocity in meters per second up to terminal velocity =
= (gravity) * (seconds)
where:
• Gravitational constant = 9.806 meters per second squared
distance traveled =
= 0.5 * (gravity) * ((seconds)^2)
estimated velocity at time of impact in meters per second =
= SQRT(2 * (distance fallen in meters) * (gravity))
kinetic energy at impact in Joules =
= 0.5 * (kilograms) * ((terminal velocity in m/s)^2)
Interpretation:
• A kinetic energy > 136 Joules may be associated with death.
• A person landing into something that cushions the blow may survive despite a high kinetic energy.
• It is uncommon for a person to reach terminal velocity unless they have fallen quite a distance (over 100 meters).
