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Author Topic: Accident on El Cap  (Read 1406 times)

Admin Al

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Re: Accident on El Cap
« Reply #15 on: May 24, 2013, 02:38:31 PM »

terminal velocity or no, that's a helluva long fall onto a static line and not something I EVER want to experience.
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strandman

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Re: Accident on El Cap
« Reply #16 on: May 24, 2013, 07:15:34 PM »

BITD Charles Cole, founder of 5.10 was trying the second ascent of Space, then the hardest El Cap nail up,, solo... i was there, this happened.
He reachedto clip the anchors on an "A5" pitch and missed-- he ripped the ptich ! everything , about 135"  TIMES TWO.. all air so he lived THEN all the gear came sliding down the rope and knocked him out-- I am not shitting you

Wake up, solo, 40' from the wall, bleeding and you gotta jug back up  Two days to down aid/escape
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kenreville

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Re: Accident on El Cap
« Reply #17 on: May 24, 2013, 08:42:02 PM »

Mark, 230 feet is about 50 feet short of the 'height' of the Brooklyn Bridge. 
So I did some Googling and came up with this paper - http://people.math.gatech.edu/~weiss/pub/v2II.pdf
One of its conclusion is "Consider a 54-kilogram person who jumped feet first off the Brooklyn Bridge into the water, a fall of 84.4 m (280 feet).  The jumper would hit the water moving about 28 m/s .... ".   about 63 mph which is about one half of the terminal velocity of a human.  So I way underestimated how far one has to fall to reach terminal velocity.  I looked that up too and it seems like a 600 foot free fall will result in the human body reaching 90% terminal velocity.  Grim.

Falling onto a stretched out gym rope while setting routes suck in general; 30~50 feet of rope out, self belaying with a Gri-Gri.  Much more jarring than a good catch from a belayer using a dynamic rope.

It's kinematics. Fundamental equation is: Velocity final (squared) = Velocity initial (squared) + 2 (acceleration)(distance). In this tragedy, his initial velocity was 0. Acceleration due to gravity is either 32ft/secsec or 9.8m/secsec- take your pick. If he fell 230 ft, he was therefore going, about 86ft/sec or 58.6 mph.

Overly simplistic although typical Physics 101 answer.  Ignores (air) resistence which is related to surface area and weight.  At 230 feet this will be a significant factor - remember the feather, the cannonball and the vaccum.  Thus the whole concept of TERMINAL velocity.  Which varies with elevation (atmospheric density).

Sorry Eric, but you'd be wrong. First off, air resistance has NOTHING to do with weight. Surface area does have some effect, but is negligible. Take two dissimilar shaped objects of different weight, drop them off a bridge, they'll hit the ground at the same time. I have know idea what the mean by the feather etc. You are correct that terminal velocity varies greatly with atmospheric pressure (hence density). The difference between the atmospheric pressure in Yosemite Valley and sea level would effect the kinematic equation very little. Jump out of a plane in the earth's upper reaches of the atmosphere, and you've got a point. 
« Last Edit: May 24, 2013, 08:54:01 PM by kenreville »
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M_Sprague

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Re: Accident on El Cap
« Reply #18 on: May 24, 2013, 08:52:05 PM »

BITD Charles Cole, founder of 5.10 was trying the second ascent of Space, then the hardest El Cap nail up,, solo... i was there, this happened.
He reachedto clip the anchors on an "A5" pitch and missed-- he ripped the ptich ! everything , about 135"  TIMES TWO.. all air so he lived THEN all the gear came sliding down the rope and knocked him out-- I am not shitting you

Wake up, solo, 40' from the wall, bleeding and you gotta jug back up  Two days to down aid/escape

He should have been wearing a rastahat. I always put on my thick wool hat if I am doing something sketchy.
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strandman

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Re: Accident on El Cap
« Reply #19 on: May 24, 2013, 09:16:32 PM »

Charles was " fully equipped"
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OldEric

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Re: Accident on El Cap
« Reply #20 on: May 25, 2013, 09:40:33 AM »


Sorry Eric, but you'd be wrong. First off, air resistance has NOTHING to do with weight. Surface area does have some effect, but is negligible. Take two dissimilar shaped objects of different weight, drop them off a bridge, they'll hit the ground at the same time. I have know idea what the mean by the feather etc. You are correct that terminal velocity varies greatly with atmospheric pressure (hence density). The difference between the atmospheric pressure in Yosemite Valley and sea level would effect the kinematic equation very little. Jump out of a plane in the earth's upper reaches of the atmosphere, and you've got a point.

It's clear that you have "know" idea.  "No" idea either  :).  Classic example in Newtonian physics is dropping an equal weigh of feathers vs. lead in a vacuum or in the atmosphere.  Goggle can help you know things.  Surface area is far from negligible in the real world.
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kenreville

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Re: Accident on El Cap
« Reply #21 on: May 25, 2013, 10:57:40 AM »


Sorry Eric, but you'd be wrong. First off, air resistance has NOTHING to do with weight. Surface area does have some effect, but is negligible. Take two dissimilar shaped objects of different weight, drop them off a bridge, they'll hit the ground at the same time. I have know idea what the mean by the feather etc. You are correct that terminal velocity varies greatly with atmospheric pressure (hence density). The difference between the atmospheric pressure in Yosemite Valley and sea level would effect the kinematic equation very little. Jump out of a plane in the earth's upper reaches of the atmosphere, and you've got a point.

It's clear that you have "know" idea.  "No" idea either  :).  Classic example in Newtonian physics is dropping an equal weigh of feathers vs. lead in a vacuum or in the atmosphere.  Goggle can help you know things.  Surface area is far from negligible in the real world.

From Wikepedia: "A biography by Galileo's pupil Vincenzo Viviani stated that Galileo had dropped balls of the same material, but different masses, from the Leaning Tower of Pisa to demonstrate that their time of descent was independent of their mass.[118] This was contrary to what Aristotle had taught: that heavy objects fall faster than lighter ones, in direct proportion to weight."

If a person is wearing a wingsuit, and presents a foil profile they will obviously go faster. What I stated is that two random dissimilar shaped objects of different mass will fall at exactly the same speed. The difference in air density between Yosemite and sea level is insignificant. Hence,the laws of kinematics provide an accurate description of terminal velocity. Certainly, a man's body is a random shaped object. When he fell, if you released a lead BB at the same spot/time, they would both hit the ground at exactly the same time.

Once again Eric, sorry bud but you're WRONG. Ya just can't beat science.
BTW- I have a degree in engineering so I do know a little bit about the subject.

So Eric, what's your background/ reference to what you claim? 
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M_Sprague

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Re: Accident on El Cap
« Reply #22 on: May 25, 2013, 11:38:44 AM »

So Eric, what's your background/ reference to what you claim?
Old codger, but he has a couple smartypants kids who can check his math for him.  ;)
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tradmanclimbz

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Re: Accident on El Cap
« Reply #23 on: May 25, 2013, 03:32:32 PM »

Dude yer full a shit. You are telling us that a 70kg  basejumper with a chute will fall off of El cap at the same speed as a 70kg pig w/ no chute.  You seem to be trying to tell us that areo dynamics do not mean anything.....
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danf

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Re: Accident on El Cap
« Reply #24 on: May 25, 2013, 05:49:56 PM »

As long as the basejumper hasn't deployed the chute, then yes, I believe that is what he is saying, at least for the short fall (230') that's being discussed.  The rate of acceleration is the same regardless of mass.  A feather won't fall nearly as fast as a ball of the identical mass, simply because the surface area of the feather is exponentially greater, thus a lower terminal velocity. 

Ken, correct me if I'm wrong, but for short falls like you are talking about, surface area won't play a major factor unless the surface area to mass ratio is huge (i.e.-feather).  For longer falls like skydiving, then yes, surface area will play a small part, thus the reason tandem jumpers need a small braking chute. 
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tradmanclimbz

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Re: Accident on El Cap
« Reply #25 on: May 25, 2013, 06:07:35 PM »

Anyone who has ever ridden a bicycle into the wind knows how much wind resistance has to do with any kind of forward movement. even slight changes in your posture make a huge difference.
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strandman

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Re: Accident on El Cap
« Reply #26 on: May 25, 2013, 06:33:04 PM »

As someone with a pretty extensive surface area (and mass)....  ;) just saying
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tradmanclimbz

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Re: Accident on El Cap
« Reply #27 on: May 25, 2013, 07:01:05 PM »

BTW I have no idea what you guys are babbleing about. i simply jumped in swinging when I saw someone saying words to the affect that areodynamics had nothing to do with falling speed....  rainy day   :-[
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kenreville

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Re: Accident on El Cap
« Reply #28 on: May 25, 2013, 08:16:02 PM »

Dude yer full a shit. You are telling us that a 70kg  basejumper with a chute will fall off of El cap at the same speed as a 70kg pig w/ no chute.  You seem to be trying to tell us that areo dynamics do not mean anything.....

No "dude"- the issue is your comprehension. My initial response was with respect to the velocity at which this man hit mother earth. My response:

"It's kinematics. Fundamental equation is: Velocity final (squared) = Velocity initial (squared) + 2 (acceleration)(distance). In this tragedy, his initial velocity was 0. Acceleration due to gravity is either 32ft/secsec or 9.8m/secsec- take your pick. If he fell 230 ft, he was therefore going, about 86ft/sec or 58.6 mph."

The assinine non-scientific incorrect response:

"Overly simplistic although typical Physics 101 answer.  Ignores (air) resistence which is related to surface area and weight.  At 230 feet this will be a significant factor - remember the feather, the cannonball and the vaccum.  Thus the whole concept of TERMINAL velocity.  Which varies with elevation (atmospheric density)."

My response to the assinine response:

"Sorry Eric, but you'd be wrong. First off, air resistance has NOTHING to do with weight. Surface area does have some effect, but is negligible. Take two dissimilar shaped objects of different weight, drop them off a bridge, they'll hit the ground at the same time. I have know idea what the mean by the feather etc. You are correct that terminal velocity varies greatly with atmospheric pressure (hence density). The difference between the atmospheric pressure in Yosemite Valley and sea level would effect the kinematic equation very little. Jump out of a plane in the earth's upper reaches of the atmosphere, and you've got a point."

The next ill informed response:

"It's clear that you have "know" idea.  "No" idea either  :).  Classic example in Newtonian physics is dropping an equal weigh of feathers vs. lead in a vacuum or in the atmosphere.  Goggle can help you know things.  Surface area is far from negligible in the real world."

Let me get out the crayons and make this as simple as possible. If there was no atmosphere, a free falling body of any shape/any mass in outer space traveling at velocity V, enters the gravitational field of the earth and accelerates at a constant rate. It will hit the earth at: (time for the crayons) Velocity final (squared) = Velocity initial (squared) + 2 (acceleration)(distance). The only thing "air resistance" does is provide a limit. Closer to earth, the air is more dense so an object reaches it's terminal velocity at a slower speed than if the air is less dense. FACT IS- a man that falls 240 ft off a cliff in Yosemite Valley is still accelerating due to gravity and HAS NOT reached the limit that the air resistance provides.
Classic Galileo kinematics describes what physically happens in this case quite accurately.

If you don't know what the hell you're talking about, usually better to keep the trap shut. Just sayin'.

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tradmanclimbz

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Re: Accident on El Cap
« Reply #29 on: May 25, 2013, 08:25:58 PM »

damn. It took a hell of a lot of words to say that wind resistance will keep someone from hitting terminal velocity in 240ft. you are dealing mostly  with simpletons here. keeping it down to the crayon level helps get the point accross :-*
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