Editing Terminal velocity (section)

==Examples==
[[File:Graph of velocity versus time of a skydiver reaching a terminal velocity.svg|thumb|Graph of velocity versus time of a skydiver reaching a terminal velocity.]]

Based on air resistance, for example, the terminal speed of a [[skydiving|skydiver]] in a belly-to-earth (i.e., face down) [[free fall]] position is about {{convert|55|m/s|ft/s|round=5|abbr=on}}.<ref name="Huang1999">{{cite web
| url=https://hypertextbook.com/facts/1998/JianHuang.shtml
| title=Speed of a skydiver (terminal velocity)
| first=Jian
| last=Huang
| year=1998
| website=The Physics Factbook
| editor-last=Elert
| editor-first=Glenn
| accessdate=2022-01-25
}}</ref> This speed is the [[asymptotic]] limiting value of the speed, and the forces acting on the body balance each other more and more closely as the terminal speed is approached. In this example, a speed of 50.0% of terminal speed is reached after only about 3 seconds, while it takes 8 seconds to reach 90%, 15 seconds to reach 99%, and so on.

Higher speeds can be attained if the skydiver pulls in their limbs (see also [[freeflying]]).<ref name="Huang1999" /> In this case, the terminal speed increases to about {{convert|90|m/s|ft/s|abbr=on|-1}},{{Citation needed|date=October 2024}} which is almost the terminal speed of the [[peregrine falcon]] diving down on its prey.<ref>{{cite web |url=http://www.fws.gov/endangered/recovery/peregrine/QandA.html |archive-url=https://web.archive.org/web/20100308202440/http://www.fws.gov/endangered/recovery/peregrine/QandA.html |title=All About the Peregrine Falcon |publisher=U.S. Fish and Wildlife Service |date=December 20, 2007|archive-date=March 8, 2010}}</ref> The same terminal speed is reached for a typical [[.30-06 Springfield|.30-06]] bullet dropping downwards—when it is returning to the ground having been fired upwards or dropped from a tower—according to a 1920 U.S. Army Ordnance study.<ref>{{cite web |url=http://www.loadammo.com/Topics/March01.htm |title=Bullets in the Sky |author=The Ballistician |publisher=W. Square Enterprises, 9826 Sagedale, Houston, Texas 77089 |date=March 2001 |url-status=dead |archive-url=https://web.archive.org/web/20080331192517/http://www.loadammo.com/Topics/March01.htm |archive-date=2008-03-31 }}</ref>

Competition [[Speed skydiving|speed skydivers]] fly in a head-down position and can reach speeds of {{convert|150|m/s|ft/s|abbr=on|sigfig=2}}.{{citation needed|date=January 2022}} The current record is held by [[Felix Baumgartner]] who jumped from an altitude of {{convert|127582|ft|m|abbr=on|order=flip}} and reached {{convert|380|m/s|ft/s|abbr=on|sigfig=2}}, though he achieved this speed at high altitude where the density of the air is much lower than at the Earth's surface, producing a correspondingly lower drag force.<ref>{{cite journal|title=Physiological Monitoring and Analysis of a Manned Stratospheric Balloon Test Program|last1=Garbino|first1=Alejandro|last2=Blue|first2=Rebecca S.|last3=Pattarini|first3=James M.|last4=Law|first4=Jennifer|last5=Clark|first5=Jonathan B.|journal=[[Aviation, Space, and Environmental Medicine]]|date=February 2014|volume=85|issue=2|pages=177–178|doi=10.3357/ASEM.3744.2014|pmid=24597163 |doi-access=free}}</ref>
 
The biologist [[J. B. S. Haldane]] wrote, {{Quote|To the mouse and any smaller animal [gravity] presents practically no dangers. You can drop a mouse down a thousand-yard mine shaft; and, on arriving at the bottom, it gets a slight shock and walks away. A rat is killed, a man is broken, a horse splashes. For the resistance presented to movement by the air is proportional to the surface of the moving object. Divide an animal's length, breadth, and height each by ten; its weight is reduced to a thousandth, but its surface only to a hundredth. So the resistance to falling in the case of the small animal is relatively ten times greater than the driving force.<ref>{{cite magazine |last=Haldane |first=J. B. S. |author-link=J. B. S. Haldane |date=March 1926 |title=On Being the Right Size |title-link=On Being the Right Size |magazine=Harper's Magazine |volume=March 1926 }}</ref>}}