Cooking For Engineers Forum Index Cooking For Engineers
Analytical cooking discussed.
 
 FAQFAQ   SearchSearch   MemberlistMemberlist   UsergroupsUsergroups   RegisterRegister 
 ProfileProfile   Log in to check your private messagesLog in to check your private messages   Log inLog in 

What is the terminal velocity of a human being?

 
Post new topic   Reply to topic    Cooking For Engineers Forum Index -> Useless Stuff Comments Forum
View previous topic :: View next topic  
Author Message
Michael Chu



Joined: 10 May 2005
Posts: 1626
Location: Austin, TX (USA)

PostPosted: Sat Jul 16, 2005 10:23 pm    Post subject: What is the terminal velocity of a human being? Reply with quote


Article Digest:
Most people quote 55 m/s (about 125 miles per hour) as the terminal velocity of a parachuter. This is a typical terminal velocity, but there are several factors that can contribute to the terminal velocity of a human.

Terminal velocity is the speed at which a falling object no longer accelerates while falling. As every grade school science student can tell you, all objects fall at the same rate in a vaccum (or more correctly, accelerate at the same rate). However, in an atmosphere, drag comes into play. Falling through air causes drag proportional to the cross sectional area of the object falling. When the drag forces offset the weight of the object (mass times gravitational acceleration), terminal velocity is reached.

A parachuter can spread out their arms and legs to increase drag resulting in the a terminal velocity of about 55 m/s. If the parachuter tucked in his arms and legs and curled up into a ball, then terminal velocity would be much faster. A parachuter wearing special equipment and diving head first or feet first with arms clasped tight against their side, can achieve terminal velocities over 90 m/s (200 miles per hour).

The fastest speed a human has ever attained while free falling was set by Joseph Kittinger, who, in 1960, jumped from over 31,000 m (over 101,000 ft). Because of the rarity of the atmosphere at those elevations, there was almost no drag during the first part of his fall. Kittinger reached a terminal velocity of 274 m/s (over 610 miles per hour) before he began to slow down with the increasing atmosphere.
Back to top
View user's profile Send private message Send e-mail
ldyvic



Joined: 03 Feb 2006
Posts: 7
Location: U.S.A.

PostPosted: Fri Feb 03, 2006 3:56 pm    Post subject: Question? Reply with quote

Did the guy from 1960's have and adverse effects of going that fast?

Like not being able to breath during his free fall?
Back to top
View user's profile Send private message Send e-mail Yahoo Messenger MSN Messenger
Ronin



Joined: 13 Dec 2005
Posts: 3

PostPosted: Wed Feb 15, 2006 3:07 pm    Post subject: Reply with quote

He was in a full pressure suit. Take a look http://www.centennialofflight.gov/essay/...EX31.htm
Back to top
View user's profile Send private message
Howard



Joined: 21 Nov 2005
Posts: 64

PostPosted: Fri May 04, 2007 6:06 am    Post subject: Reply with quote

African or European?
Back to top
View user's profile Send private message
peter grimes



Joined: 20 Mar 2010
Posts: 1

PostPosted: Sat Mar 20, 2010 6:04 pm    Post subject: Reply with quote

Kittinger blacked out for a while during that jump. His first chute deployed in such a way as to throw him into a spin. He was rotating so fast that he lost consciousness. He regained consciouness a minute or so later and was able to successfully complete the jump.

But his jump is about to be eclipsed by an attempt from even higher up:

The Red Bull Stratos jump.

Rhett Allain has done a wonderful analysis of the forces involve. Mind you, there are a lot of assumptions, but he is diligent in noting the sources of error.
Back to top
View user's profile Send private message
akashtab



Joined: 15 Feb 2012
Posts: 6

PostPosted: Thu Mar 08, 2012 10:36 am    Post subject: Reply with quote

I guess that would not be any terminal velocity for a Human because of large weight i dont thing anytime air friction is going to exert a force equal to mg.
Back to top
View user's profile Send private message
avengers1



Joined: 26 Apr 2012
Posts: 2

PostPosted: Thu Apr 26, 2012 5:26 pm    Post subject: Reply with quote

akashtab wrote:
I guess that would not be any terminal velocity for a Human because of large weight i dont thing anytime air friction is going to exert a force equal to mg.


I believe you have mistaken the term 'terminal velocity' there =P though your point is still correct, human's can't levitate from wind resistance without a parachute to increase our effective area. Though this point is slightly off topic =)
Back to top
View user's profile Send private message AIM Address MSN Messenger
tabestmaker



Joined: 19 Jan 2013
Posts: 3

PostPosted: Tue Jan 22, 2013 11:02 am    Post subject: Reply with quote

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.
Back to top
View user's profile Send private message
Dilbert



Joined: 19 Oct 2007
Posts: 1012
Location: central PA

PostPosted: Tue Jan 22, 2013 1:52 pm    Post subject: Reply with quote

if air resistance didn't matter, there would be no terminal velocity - what is falling would continue to accelerate until the Big Splat.

terminal velocity is the point where the air / wind resistance balances the force of gravity. since air resistance changes with shape, a skydiver going headfirst&streamlined reaches a higher terminal velocity than the spread eagle position.
Back to top
View user's profile Send private message
Display posts from previous:   
Post new topic   Reply to topic    Cooking For Engineers Forum Index -> Useless Stuff Comments Forum All times are GMT
Page 1 of 1

 
Jump to:  
You cannot post new topics in this forum
You can reply to topics in this forum
You cannot edit your posts in this forum
You can delete your posts in this forum
You cannot vote in polls in this forum


Powered by phpBB © 2001, 2005 phpBB Group