Can anyone give me a rough estimate of what terminal velocity would be for a human being?
I realize that the figure will vary greatly depending on wind resistance from the position the person is in, but I’m just looking for an approximate range. Let’s assume that we’re talking an arched-back, spread-out skydiver on one hand, and a stiffened corpse dumped out the window of a tall building on the other. 30 fps? 100 fps? More?
105 - 120 mph in the pose you suggest.
I once read that terminal velocity was ABOUT 200 mph if rolled in a ball and 120 mph if spread eagle.
ISTR reading the same thing…
But is anyone else a little curious why one would want to specificly know the terminal velocity of “a stiffened corpse dumped out the window of a tall building”?
You expect us to fall for this kind of question?
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.
Kevin B.
I thought terminal velocity was in the the same range for everything. Weight doesn’t determine how fast something falls, the objects mass compared to the earth’s mass does, air resistance notwithstanding.
Heard an interview on NPR yesterday with a woman who plans to break the skydiving height record (sometime next year, I think). She plans to jump from an open gondola helium balloon at, get this, 165,000 feet (about 50km for you non-SI challenged out there)!
She will jump wearing a pressure suit, and expects to reach a maximum velocity, about 1 minute into the fall, of about Mach 1.5 (something over 1000 miles/hour). Of course, that’s only possible because the atmosphere is so thin at that altitude. She is quite an experienced skydiver, apparently, with over 14000 jumps (the highest being from 25,000 feet).
Frankly, the thought of skydiving at any height makes me want to blow chunks, but chacun a son gout.
Rick
Or about 31 miles. I’m sure she could reach some whopping speeds from that height.
J. Noble wrote:
Air resistance is why terminal velocity exists. In a vacuum, an object will fall to earth with an acceleration of roughly 9.8 meters per second per second (i.e., the velocity increases by 9.8 m/s every second the object falls).
From this, we can see that the ultimate velocity (i.e., the speed of the object just before it hits the ground) depends only on how far the object has fallen – mass has nothing to do with it. Galileo did some rather famous experiments with this at the Leaning Tower of Pisa a few hundred years ago.
A popular demonstration of this principle is often used in physics classes – a longish glass tube, with a vacuum (and a feather & a lead ball) inside is rotated vertically (so the top becomes the bottom). If the vacuum is good enough, both items will land at the bottom of the tube at the same time.
Of course, skydivers usually don’t dive in a vacuum – that’s where air resistance comes in. The equations are a bit complex (which is why I don’t remember them), but basically the air below you is pushing against you as you fall, countering in part the effects of gravity. So, by changing your orientation as you fall, you change the amount of surface area the air can press against, and thus change your terminal velocity.
Well, I’ll take the plunge.
I thought that was already done, and from even higher than that already from the Man-High program in the 60s. I will try to do some snooping on that.
Eric
http://www.wpafb.af.mil/museum/afp/afp200.htm
USAF People/museum link
http://www.cyber-quest.com/News/Default.asp?Story=6581
and one more.
The equation for figuring out terminal velocity is:
F = ½(rho)U[sup]2[/sup]SC[sub]D[/sub]
U is the velocity
rho is the density of air (at sea level 0.002377 slugs per cubic foot)
S is the frontal area
C[sub]D[/sub] is the coefficient of drag
F is the resultant force that this causes, which at terminal velocity is equal to the weight of the object.
Just keep your slugs and your cubic feet away from my frontal area, thank you.
Here’s another fun formula.
The terminal velocity of a spherical object is (2/9)(r[sup]2[/sup]g/n)(p-p’) where r=radius of the sphere, n=viscosity of the fluid it is falling thru, p=density of the sphere, and p’=the density of the fluid.
That should settle a lot of bar bets.
For more discussion…
SDMB - Terminal Velocity
SDMB - 2 Skydiving Questions
Also you can check out Outside Magazine’s November issue where there is a short article in their Dispatches section about Cheryl Stearns’ upcoming record attempt. Jumping at 130,000 feet and reaching a speed of Mach 1.3. The article continues to state that it will be the first time a human has broken the sound barrier unaided. They do mention Kittinger’s jump, current record, but don’t mention that he also claims to have hit the sound barrier. We have discussed his claims in one of the above threads IIRC.
Could he mean* how fast does a human being have to be going before he is killed?* 
This would explain his confusion over the “terminal velocity” of a cadaver vs. the same for a human.
Possible semantic problem, here.
But he did said “a stiffened corpse dumped out the window”. That seems to indicate that he wanted to know difference between the terminal velocity for a stiff, tumbling body vs. a live one.
In either case, I’d think you’d have to fall pretty far after dying to be stiff before you hit the ground…