Cooking For Engineers

[Michael Chu]

Go to What is the terminal velocity of a human being?

Article Digest:
Most people quote 55 m/s (about 125 miles per hour) as the terminal velocity of a parachuter. This is a typical terminal velocity, but there are several factors that can contribute to the terminal velocity of a human.

Terminal velocity is the speed at which a falling object no longer accelerates while falling. As every grade school science student can tell you, all objects fall at the same rate in a vaccum (or more correctly, accelerate at the same rate). However, in an atmosphere, drag comes into play. Falling through air causes drag proportional to the cross sectional area of the object falling. When the drag forces offset the weight of the object (mass times gravitational acceleration), terminal velocity is reached.

A parachuter can spread out their arms and legs to increase drag resulting in the a terminal velocity of about 55 m/s. If the parachuter tucked in his arms and legs and curled up into a ball, then terminal velocity would be much faster. A parachuter wearing special equipment and diving head first or feet first with arms clasped tight against their side, can achieve terminal velocities over 90 m/s (200 miles per hour).

The fastest speed a human has ever attained while free falling was set by Joseph Kittinger, who, in 1960, jumped from over 31,000 m (over 101,000 ft). Because of the rarity of the atmosphere at those elevations, there was almost no drag during the first part of his fall. Kittinger reached a terminal velocity of 274 m/s (over 610 miles per hour) before he began to slow down with the increasing atmosphere.

[ldyvic]

Did the guy from 1960's have and adverse effects of going that fast?

Like not being able to breath during his free fall?

[Ronin]

He was in a full pressure suit. Take a look http://www.centennialofflight.gov/essay/...EX31.htm

[Howard]

African or European?

[peter grimes]

Kittinger blacked out for a while during that jump. His first chute deployed in such a way as to throw him into a spin. He was rotating so fast that he lost consciousness. He regained consciouness a minute or so later and was able to successfully complete the jump.

But his jump is about to be eclipsed by an attempt from even higher up:

The Red Bull Stratos jump.

Rhett Allain has done a wonderful analysis of the forces involve. Mind you, there are a lot of assumptions, but he is diligent in noting the sources of error.

[akashtab]

I guess that would not be any terminal velocity for a Human because of large weight i dont thing anytime air friction is going to exert a force equal to mg.

[avengers1]

[tabestmaker]

I remember the Guinness Book Of World Records touting skydiving as the fastest nonmotorized sport (I guess they don't count the airplane motors). They claimed that a skydiver can reach 185 mph in a headfirst freefall.

[Dilbert]

if air resistance didn't matter, there would be no terminal velocity - what is falling would continue to accelerate until the Big Splat.

terminal velocity is the point where the air / wind resistance balances the force of gravity. since air resistance changes with shape, a skydiver going headfirst&streamlined reaches a higher terminal velocity than the spread eagle position.