Just read this article on Yahoo.
http://news.yahoo.com/s/space/20060713/sc_space/spacediverpreparesforbigjump (http://news.yahoo.com/s/space/20060713/sc_space/spacediverpreparesforbigjump)
This part bothers me:
QuoteIf successful, Fournier will beat four world parachutist's records from the border of space:
Altitude record for freefall
Altitude record for human balloon flight
Time record for longest freefall
Speed record for fastest freefall--breaking the sound barrier in the process
Now I've not had physics in a few years, but shouldn't terminal velocity prohibit a freefaller from reaching super sonic speeds? Granted, up that high the air is thinner, so he'd start falling slower the closer he got to earth, but wouldn't the change in gravity at that height kinda negate that? And if not, shouldn't it still be impossible to freefall faster than the speed of sound?
:-\
Uhhh.
/blink
Heh. I teach elementary school. Ya got me.
So, got Brother spam and thought I'd upload it here, because it is SO appropriate to this thread...and funny :)
Why Grandmas Shouldn't Skydive (http://www.youtube.com/watch?v=ijj39A6b1Wc&search=dentures)
Can't...breath...
Laughing...so...hard....!
:2funny:
Terminal velocity and the speed of sound are different concepts. Both values are dependent on air density (i.e. air pressure), and in the case of the speed of sound air temperature. Terminal velocity is dependent on several other characteristics of the falling body.
So I suppose it is a technical possibility that someone could exceed the speed of sound while falling if they were in a low-pressure environment like 25 km above the surface of the earth. The two formulae vary by a factor of (1/Rho)^-0.5 but the other factors in the formulae may allow for a cross-over at some point. I'm too lazy to run the actual calculations though.
Hmm, good point. I hadn't thought about the speed of sound being different up there as well.
That might just explain it!
TY, that was really bothering me!
Physical properties of the falling object are important, too, especially when air density increases. A very aerodynamic object will fall much faster than one that is not. I suspect that our plummeting recordbreaker will be making use of this fact.
The person or object will continually accelerate until the resistance of the air equals gravitation. A geosynchronous orbit or geostationary orbit (stays in one place matching the rotation of the Earth) travels 22,300 miles above the Earth so you can see how strong the Earth's gravitation is out that far. The atmosphere reaches over 560 kilometers (348 miles) from the surface of the Earth, and he is jumping at 130,000 feet (40 kilometers)--roughly 25 miles above the Earth so he is not even close to the outer edge of it. With little to no air resistance to start out with, I would think a person could easily break the sound barrier before the air gets thick enough to slow him down. I am not sure how thick it is at 25 miles but sure it is still thin enough to get going that fast.
The real question is how he will not burn up like an asteroid does. I would think the friction would cook him once he starts to slow down from going that fast. I guess there is enough air drag at 25 miles high he will not have that problem.
He's supposedly wearing some super suit, I guess to prevent him from burning up.
But the French made it...and while they are very fashion conscious, I don't know how good they are at keeping things unburnt.