Skydiver gets ready for 23 mile jump

[Herr-Berbunch]

Originally Posted by Sailor Steve

No worse than any other. It will be no difference than if he jumped at 6000 feet and pulled the cord at 5000. The drag is all the same.

Iirc you are still accelerating after 1000', but not for much.

[Sailor Steve]

Originally Posted by Tribesman

Doesn't terminal velocity mainly revolve around the principle of a lack of further acceleration?

As the air gets thicker drag increases, and the object slows down. He may be close to mach 1 at 100,000 feet, but at 5000 feet he'll be down to about 120 mph, or 200 kph.

What if he sticks his arm out or doesn't? either from a plane at 20,000 or from a balloon at 120,000? what if he sticks both arms out in an las vegas elvis suit?

With the arms out the drag is increased. If the diver keeps his arms tucked at his sides he'll fall a little faster.

From the article I linked

A person has a terminal velocity of about 200 mph when balled up and about 125 mph with arms and feet fully extended to catch the wind.

[Osmium Steele]

Originally Posted by Tribesman

Doesn't terminal velocity mainly revolve around the principle of a lack of further acceleration?

What if he sticks his arm out or doesn't? either from a plane at 20,000 or from a balloon at 120,000? what if he sticks both arms out in an las vegas elvis suit?

Many things determine "terminal" velocity, I'll not go into all of them here. Even wikipedia has a decent entry.

Air density has a huge effect on the speed at which an object falls.

In a vacuum, a bowling ball and a feather would drop at the same speed, not so in the atmosphere.

Now, assuming the object is not falling in a vacuum, then cross sectional area of the falling object exposed to the passing atmosphere has an effect on velocity.

A jumper diving head down with arms and legs straight will fall quite a bit faster than the same jumper spread eagle.

What is a parachute other than an object which increases your cross-sectional area against the atmosphere?

As the air gets thicker drag increases, and the object slows down

Many things determine "terminal" velocity,

Yes, and I was wondering what the rate of decelaration due to thicker air would be and how rapidly his high velocity would be reduced, plus how far would he travel before that effect is finished and he would again be at a "terminal velocity".
@Steve, I was just pointing out that it wasn't a constant.
@Osmium, you understand why this is actually a variable...he'll be going no faster than if he'd jumped from an airplane.

[Osmium Steele]

Originally Posted by Tribesman

Yes, and I was wondering what the rate of decelaration due to thicker air would be and how rapidly his high velocity would be reduced,

Ah, Ok. That's too many maths , and dependent upon a whole set of variables including his own movements/actions a the time.

Even air density at a given altitude is variable based on a number of factors. Too many variables to give a solid answer, and since he will be falling, the value would be ever changing.

Let me see if I can find a chart somewhere that shows a baseline human freefall velocity at various altitudes. Should be something on the intarwebs somewhere.

Edit: Check this out. Skydiving Fall Rate

Hope that gives you the info you seek.

Hope that gives you the info you seek.

Not really as none have the very high initial speed gained before hitting those heights with denser air, plus of course the old record jump has an early small chute depoyment so his pattern would be very different as his air resitance would be massively altered.

[Osmium Steele]

An interesting tidbit I hadn't previously read. Kittinger's instruments showed he continued to accelerate for a bit even after the drogue deployed at 93,000 feet.

Guess the air is a might thin up there.

An interesting tidbit

It was that tidbit that set me wondering in the first place.