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Author Topic: Accident on El Cap  (Read 1543 times)

sneoh

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Re: Accident on El Cap
« Reply #30 on: May 25, 2013, 09:47:17 PM »

That is right, if there were no atmosphere, there would be no terminal velocity and everything would fall at the same rate.

But on this planet, a feather would reach a lower terminal velocity in a shorter distance than say a bowling ball.
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OldEric

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Re: Accident on El Cap
« Reply #31 on: May 25, 2013, 10:12:22 PM »

According to his original formula:

It's kinematics. Fundamental equation is: Velocity final (squared) = Velocity initial (squared) + 2 (acceleration)(distance).

There isn't even such a concept as terminal velocity.  Plugging numbers in you see that as distance approaches vicinity so does velocity.  And that was the just the beginning...
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kenreville

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Re: Accident on El Cap
« Reply #32 on: May 25, 2013, 10:29:56 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 :-*
That's NOT what I said at all. Wind resistance HAS NOTHING TO DO WITH IT!!!!
The point at which a free falling body REACHES terminal velocity is when the mass x the acceleration due to gravity EQUALS the opposite force that wind resistance applies. At that point, acceleration stops and the object has reached terminal velocity. Terminal velocity for an object at 1 atmosphere of pressure (sea level) is approximately 120mph. The man we are talking about did not fall far enough to reach that speed, HENCE HE WAS STILL ACCELERATING.

Please stop with the "wind resistance" schtick. You're embarrassing yourself.
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kenreville

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Re: Accident on El Cap
« Reply #33 on: May 25, 2013, 10:34:39 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.

Anyone who payed attention during high school physics knows that you're "analogy" is missing one HUGE component.
The constant acceleration of an object due to gravity.

You boys should give it up.
Really.
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kenreville

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Re: Accident on El Cap
« Reply #34 on: May 25, 2013, 10:41:04 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.

Now here's a guy who gets it. You are 100%  correct.
Kinda a shame that there's climbers that don't understand forces and gravity.
Hope they don't get hurt.
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kenreville

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Re: Accident on El Cap
« Reply #35 on: May 26, 2013, 01:43:24 PM »

Just re-checked my math. Looks like I made an algebra error.

Vf^2=Vi^2+(2)(a)(d)  where Vf=velocity final, Vi=0=velocity initial, a=acceleration due to gravity, d=distance.

Vf^2=0+(2)(32ft/s^2)(230ft)
Vf^2=14720 ft^2/s^2
Vf=121 ft/sec=83 miles/hour

Regardless, everything else I stated is true. Since approx 120mph is terminal velocity for a free falling human at sea level not trying to alter his wind resistance (like a guy that just had his rope chopped), this man had not yet reached that point where his mass x gravitational acceleration equalled the opposing wind resistance vector. Hence this statement is absolutely incorrect:

"Overly simplistic although typical Physics 101 answer.  Ignores (air) resistence which is related to surface area and weight."
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tradmanclimbz

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Re: Accident on El Cap
« Reply #36 on: May 26, 2013, 04:27:23 PM »

all we really need to know is that gravity always wins. Be methodical, check everything twice and pray the mountain does not fall down on you...




Am i the only one who says a few prayers every time I slither behind and on top of the Fickle Finger of Fate?
And then there is ice climbing.... :-\
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DGoguen

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Re: Accident on El Cap
« Reply #37 on: May 26, 2013, 05:23:43 PM »

The Beast Flake as well.

« Last Edit: May 26, 2013, 05:52:37 PM by DGoguen »
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tradmanclimbz

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Re: Accident on El Cap
« Reply #38 on: May 26, 2013, 05:58:00 PM »

I have often felt that there was a risk of a cut rope on the beast flake. that thing is razor sharp down low and if for some reason your rope worked it's way into the crack i can see a scenario where it could cut in a fall by leader or 2nd. I try to sling accordingly but murphy has his ways... I have had a cam wire get sliced through in that crack simply by rotating against the edge with rope drag.
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kenreville

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Re: Accident on El Cap
« Reply #39 on: May 26, 2013, 06:05:52 PM »

I have often felt that there was a risk of a cut rope on the beast flake. that thing is razor sharp down low and if for some reason your rope worked it's way into the crack i can see a scenario where it could cut in a fall by leader or 2nd. I try to sling accordingly but murphy has his ways... I have had a cam wire get sliced through in that crack simply by rotating against the edge with rope drag.

I agree with you on the beast flake. There are numerous other "slice fests" that I can think of here in the White Mtns.
Solution?
Double ropes.
« Last Edit: May 26, 2013, 06:14:23 PM by kenreville »
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DGoguen

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Re: Accident on El Cap
« Reply #40 on: May 26, 2013, 06:26:17 PM »

Even if you peel the entire Beast Flake, it's comforting to know that there would be guys around that could calculate your speed as you surfed it through the development below. I give you all permission to disregard wind resistance if I'm the one. Ha
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kenreville

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Re: Accident on El Cap
« Reply #41 on: May 26, 2013, 06:28:23 PM »

I'll be there with my calculator.  ;D
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slink

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Re: Accident on El Cap
« Reply #42 on: May 26, 2013, 06:34:44 PM »

I'll be there with my calculator.  ;D
Do you and old Eric have pocket protectors too. Reality is that gravity wins every time.
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bailing is not failing!!!

kenreville

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Re: Accident on El Cap
« Reply #43 on: May 26, 2013, 06:40:01 PM »

Pocket protector? Nah.

Hell, I'm 54 and sometimes get up to go to work and CHOOSE to freeball the day.

Just cause it feels good and makes scratchin easier.
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