3 ms·

From a quick Google search, the terminal velocity of a human being is roughly 120 mph. The speed of sound (at sea level) is 761 mph. How is this feat possible?

by tkahn6 16y ago

smitjel 16y ago
My thoughts exactly...I'm sure he'll be carrying extra weight but I still don't see how this is possible given a certain terminal velocity, like you said. *Edit...wikipedia says current world record is 614 mph set by Joseph Kittinger. He used the head down method in high altitude, less dense air. That's still not supersonic though.
- hnal943 16y ago
  Kittinger wasn't as high up, the extra height should give Baumgartner more time to build speed.
- zck 16y ago
  As mentioned in the article, Kittinger "only" jumped from 102,800 feet. Baumgartner will jump from 120,000. Also, Kittinger was in a "rocking chair" position, not head-down. (http://en.wikipedia.org/wiki/Joseph_Kittinger http://en.wikipedia.org/wiki/Joseph_Kittinger)
zck 16y ago
The air's much thinner up there (99% of the atmosphere is below 20 miles up: http://www.albany.edu/faculty/rgk/atm101/structur.htm http://www.albany.edu/faculty/rgk/atm101/structur.htm). Also important -- the 120 mph seems to be in a spreadeagle position.
j-g-faustus 16y ago
Terminal velocity depends on the drag/friction from the air, at higher altitudes the air is thinner. So less drag and higher terminal velocity. The current world record is ~600 mph. http://en.wikipedia.org/wiki/Terminal_velocity#Examples http://en.wikipedia.org/wiki/Terminal_velocity#Examples
pvg 16y ago
The terminal velocity is much higher in this case because the skydiver is assuming a position that minimizes drag and the air is much less dense at the altitudes in question. Additionally, the lower temperature reduces the speed of sound in a smaller but still significant degree.
neurotech1 16y ago
The terminal velocity in the stratosphere is significantly higher than at sea level, and the speed of sound is lower, at around 670 mph. Joeseph Kittingers' record was 614 mph, which is not that far off the sound barrier. Pilots have ejected out at Mach 3 from a SR-71 http://www.alexisparkinn.com/sr-71_break-up.htm http://www.alexisparkinn.com/sr-71_break-up.htm In that accident, the pilot ejected without major injury, but the co-pilot was killed.
- InclinedPlane 16y ago
  Excellent article. Note though that the pilot did not technically eject, his ejection seat was ripped out of the disintegrating plane intact by aerodynamic forces. Though the experience is probably applicable to the case where a pilot were to intentionally eject at Mach 3.
storborg 16y ago
In addition to the reduced air density at altitude (as others have mentioned), body position, weight, and clothing also have a lot to do with terminal velocity. A light person wearing baggy clothes in a belly-down position might fall at only 90 mph, whereas a heavy person wearing skin-tight clothes in a head-down position could fall at 170 mph. (speeds given at lower altitudes, close to the ground)

From a quick Google search, the terminal velocity of a human being is roughly 120 mph. The speed of sound (at sea level) is 761 mph. How is this feat possible?

by tkahn6 16y ago

From a quick Google search, the terminal velocity of a human being is roughly 120 mph. The speed of sound (at sea level) is 761 mph. How is this feat possible?

smitjel 16y ago

My thoughts exactly...I'm sure he'll be carrying extra weight but I still don't see how this is possible given a certain terminal velocity, like you said. *Edit...wikipedia says current world record is 614 mph set by Joseph Kittinger. He used the head down method in high altitude, less dense air. That's still not supersonic though.

hnal943 16y ago
Kittinger wasn't as high up, the extra height should give Baumgartner more time to build speed.
zck 16y ago
As mentioned in the article, Kittinger "only" jumped from 102,800 feet. Baumgartner will jump from 120,000. Also, Kittinger was in a "rocking chair" position, not head-down. (http://en.wikipedia.org/wiki/Joseph_Kittinger http://en.wikipedia.org/wiki/Joseph_Kittinger)

zck 16y ago

The air's much thinner up there (99% of the atmosphere is below 20 miles up: http://www.albany.edu/faculty/rgk/atm101/structur.htm http://www.albany.edu/faculty/rgk/atm101/structur.htm). Also important -- the 120 mph seems to be in a spreadeagle position.

j-g-faustus 16y ago

Terminal velocity depends on the drag/friction from the air, at higher altitudes the air is thinner. So less drag and higher terminal velocity. The current world record is ~600 mph. http://en.wikipedia.org/wiki/Terminal_velocity#Examples http://en.wikipedia.org/wiki/Terminal_velocity#Examples

pvg 16y ago

The terminal velocity is much higher in this case because the skydiver is assuming a position that minimizes drag and the air is much less dense at the altitudes in question. Additionally, the lower temperature reduces the speed of sound in a smaller but still significant degree.

neurotech1 16y ago

The terminal velocity in the stratosphere is significantly higher than at sea level, and the speed of sound is lower, at around 670 mph. Joeseph Kittingers' record was 614 mph, which is not that far off the sound barrier. Pilots have ejected out at Mach 3 from a SR-71 http://www.alexisparkinn.com/sr-71_break-up.htm http://www.alexisparkinn.com/sr-71_break-up.htm In that accident, the pilot ejected without major injury, but the co-pilot was killed.

InclinedPlane 16y ago
Excellent article. Note though that the pilot did not technically eject, his ejection seat was ripped out of the disintegrating plane intact by aerodynamic forces. Though the experience is probably applicable to the case where a pilot were to intentionally eject at Mach 3.

storborg 16y ago

In addition to the reduced air density at altitude (as others have mentioned), body position, weight, and clothing also have a lot to do with terminal velocity. A light person wearing baggy clothes in a belly-down position might fall at only 90 mph, whereas a heavy person wearing skin-tight clothes in a head-down position could fall at 170 mph. (speeds given at lower altitudes, close to the ground)