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cascadeclimber Member
Joined: 04 Sep 2006 Posts: 1427 | TRs | Pics
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DIYSteve wrote: | IME 90% of Hood standard route climbers do not follow that advice. |
Agreed.
Most people don't really understand the amount of inertia that is involved in a 20 or 30 meter fall on a hard, steep slope (like would happen if a rope leader fell on 15 meter spacing). There's just no way one person is going to arrest it. And if the second comes loose the force on the next person is 400% or more higher.
I=mV^2 is a problem for roped climbers with no gear.
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filbert Member
Joined: 31 May 2010 Posts: 99 | TRs | Pics
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filbert
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Tue Feb 20, 2018 5:44 pm
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Ahhh... inertia is m*V. Kinetic energy is (1/2)mv^2. Yep, it's a serious problem.
With every passing hour our solar system comes forty-three thousand miles closer to globular cluster M13 in the constellation Hercules, and still there are some misfits who continue to insist that there is no such thing as progress.
With every passing hour our solar system comes forty-three thousand miles closer to globular cluster M13 in the constellation Hercules, and still there are some misfits who continue to insist that there is no such thing as progress.
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DIYSteve seeking hygge
Joined: 06 Mar 2007 Posts: 12655 | TRs | Pics Location: here now |
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DIYSteve
seeking hygge
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Tue Feb 20, 2018 10:14 pm
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filbert wrote: | inertia is m*V |
When I was in physics class many years ago, p = mv
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filbert Member
Joined: 31 May 2010 Posts: 99 | TRs | Pics
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filbert
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Tue Feb 20, 2018 10:26 pm
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Whoops, yes, _momentum_. Still, that V^2 term is associated with _energy_.
With every passing hour our solar system comes forty-three thousand miles closer to globular cluster M13 in the constellation Hercules, and still there are some misfits who continue to insist that there is no such thing as progress.
With every passing hour our solar system comes forty-three thousand miles closer to globular cluster M13 in the constellation Hercules, and still there are some misfits who continue to insist that there is no such thing as progress.
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Jake Robinson Member
Joined: 02 Aug 2016 Posts: 521 | TRs | Pics
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yep, kinetic energy = 1/2mv^2 i.e. double the velocity of the sliding climbers, quadruple the work required to stop them. And of course that v is always increasing due to gravity.
Although in the specific case of a human's ability to arrest a fall, maybe momentum/impulse is a better metric. I dunno, been a while since I took physics...
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cascadeclimber Member
Joined: 04 Sep 2006 Posts: 1427 | TRs | Pics
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Jake Robinson wrote: | been a while since I took physics... |
+1
My freshman Dynamics prof would be aghast at how much I've forgotten.
Point remains: A rope leader sliding 30 meters down a steep, icy slope is not likely to be arrested by the second, unless there is some running gear to help.
If you tie in on a slope like that without gear you are betting that you'll fall and your team will arrest you. If you skip the rope you're betting on yourself to not fall. I know which I prefer.
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Stefan Member
Joined: 17 Dec 2001 Posts: 5082 | TRs | Pics
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Stefan
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Wed Feb 21, 2018 9:32 am
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Many many years ago we came down the Muir Snowfield in May of one year, we had to rope up. I was front person. There were 5 of us on the rope team. We did not want to hit the Nisqually cliffs, and if the front person fell, maybe the back people could stop us. I could not see the third person back on the rope team. Snow, wind, fog. Intense.
I am not kidding. We came across the Pebble Creek sign above Panorama Point 3 different times before we finally took off our gloves, and got out our compasses and pointed in the direction of Paradise...
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DadFly Member
Joined: 02 Jul 2012 Posts: 402 | TRs | Pics Location: Redmond |
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DadFly
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Wed Feb 21, 2018 10:35 am
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One windy day on the Muir snowfield a cloud rolled in and obscured my feet. I came to a stop and was quite surprised when I hit the ground. I sat for about 60 seconds before I could see beyond my own hands.
"May you live in interesting times"
"May you live in interesting times"
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Jake Robinson Member
Joined: 02 Aug 2016 Posts: 521 | TRs | Pics
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Being in a whiteout that bad is scary. Only happened to me once, while skiing. It was so bad I couldn't tell which way was downhill and the disorientation gave me a dizzy/carsick feeling.
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Bernardo Member
Joined: 08 Feb 2010 Posts: 2174 | TRs | Pics Location: out and about in the world |
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Bernardo
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Wed Feb 21, 2018 8:27 pm
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If you join a rope team on an icy slope with 3 others, your chances of being involved in a fall incident go up about 4x. If the odds of arresting don't go up by more than this factor you're bettor off not roping. Crevases are a very different story. The odds of an incident may not increase, but the odds of a positive outcome are increased so this seems to make statistical sense.
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DIYSteve seeking hygge
Joined: 06 Mar 2007 Posts: 12655 | TRs | Pics Location: here now |
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DIYSteve
seeking hygge
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Wed Feb 21, 2018 10:07 pm
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Bernardo wrote: | If you join a rope team on an icy slope with 3 others, your chances of being involved in a fall incident go up about 4x. |
True only if you don't place running pro, of course
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