Physics debate

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Stephen
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6’3” / 191cm — 172# / 78kg, size 47 / 30 mondo

Re: Physics debate

Post by Stephen » Sat Jan 14, 2023 4:33 pm

EDIT: I did it — pushed us over the 40 page mark! Is this Thread a record-setter?

I bet that if we were all in the same room with a ski, a boot, a cable binding and one or two beers a piece, this would be straightened out in under two hours.
Just saying…
:lol:

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DG99
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Re: Physics debate

Post by DG99 » Sat Jan 14, 2023 5:07 pm

lowangle al wrote:
Sat Jan 14, 2023 3:43 pm
DG99 wrote:
Sat Jan 14, 2023 3:37 pm
Oh… I see there are other answers already. ;)
We basically said the same thing.
Yah. No doubt.

If anyone has some specific questions for my physicist daughter let me know!

I’m thinking I could do a living room demonstration, bending skis with my boots, to demonstrate alpine and telemark, with Switchbacks in both free pivot and downhill mode. I’d have to figure out how to upload to YouTube. It’s all pretty elementary though, maybe not worth the effort.



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Stephen
Posts: 1485
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Location: PNW USA
Ski style: Aspirational
Favorite Skis: Armada Tracer 118 (195), Gamme (210), Ingstad (205), Objective BC (178)
Favorite boots: Alfa Guard Advance, Scarpa TX Pro
Occupation: Beyond
6’3” / 191cm — 172# / 78kg, size 47 / 30 mondo

Re: Physics debate

Post by Stephen » Sat Jan 14, 2023 5:55 pm

I wish I could post pictures from, but I remember watching a Youtube from here of skiers from the early days of Alpine skiing, and the introduction of cable bindings to the scene.
Skiers (standing still) showing how they could lean forward on the cable binding, without falling forward, which was a big change from earlier bindings.
Obviously, this ability to lean forward without falling forward (critically, in a static position, for the purposes of this discussion) would transfer proportionally more of their static mass / weight / pressure of the ski on the snow toward the front (tip) of the ski.

Don’t be confused by the terms front and tip.
While tip does specifically mean the upturned front of the ski, it is generally used to mean the part of the ski in front of the binding. This loose use of the word tip doesn’t cause most people any problem.

And, don’t be confused by where, exactly, the weight is applied to the front of the ski — from just in front of the binding all the way to the front of the ski, where the tip leaves the snow.
In layman’s terms, it’s applied to the tip of the ski.
In scientific terms, it’s possible to measure the exact amount — at each discreet point of the front of the ski — of this additional force of the ski to the snow along the entire front of the ski, BUT, for PRACTICAL application, this information is not necessary or useful.



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TallGrass
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Re: Physics debate

Post by TallGrass » Sun Jan 15, 2023 1:55 am




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Telerock
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Re: Physics debate

Post by Telerock » Sun Jan 15, 2023 7:41 am

Thanks for the old style binding video. I had a pair of 1957 head skis, with the old cable bindings, That I found in a Vermont barn. They were embossed with the name of a previous olympic skier. I used them for lift serve at Mad River in Vermont (with my Extreme leather boots) both with the cables hooked under the clips and without. It was much easier to ski those heavy boards on crust and hardpack with the cables hooked down, and my heels “fixed” to the ski, as would be expected. I stopped doing that after a twisting fall, the skis could not release, and some pain in the knee resulted.
I still think the primary aid to skiing from cables or active bindings is the additional lateral heel support. However, I find that is offset by the restriction to “going low” where dropping my center of gravity (in a way fixed heel skiers cannot), promotes better control.
See attached photo (please disregard my “flailing” arms held out for balance and to prevent knuckle dragging).
79052462-6F05-46A0-981E-2FCEE3AD1BEC.jpeg



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Telerock
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Re: Physics debate

Post by Telerock » Sun Jan 15, 2023 7:43 am

Note in the photo, the tip/front of the skis are not spraying snow, the action is beneath the boot (and a foot or so forward and back).



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GrimSurfer
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Re: Physics debate

Post by GrimSurfer » Sun Jan 15, 2023 10:22 am

Telerock wrote:
Sun Jan 15, 2023 7:41 am
I still think the primary aid to skiing from cables or active bindings is the additional lateral heel support. However, I find that is offset by the restriction to “going low” where dropping my center of gravity (in a way fixed heel skiers cannot), promotes better control.
This is the understanding I have been promoting in this discussion. It also accords with the laws of physics.
We dreamed of riding waves of air, water, snow, and energy for centuries. When the conditions were right, the things we needed to achieve this came into being. Every idea man has ever had up to that point about time and space were changed. And it keeps on changing whenever we dream. Bio mechanical jazz, man.



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Musk Ox
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Re: Physics debate

Post by Musk Ox » Sun Jan 15, 2023 12:08 pm

TallGrass wrote:
Sat Jan 14, 2023 2:05 pm
Musk Ox wrote:
Sat Jan 14, 2023 10:57 am
GrimSurfer wrote:
Sat Jan 14, 2023 8:02 am
Nobody needs to understand how anything actually works before using it. Trust in magic. It is powerful.
I do not know the smallest thing about, say, the hydrodynamic processes relating to the way that glide is altered ... but I do know how to cork on Swix Polar and I know which snacks to take, and I do know that going up to the top of little mountains is the hobby that has brought me more joy ...
Ahh, bliss...

It's like a flashback to Page 14 (and possibly earlier)
TallGrass wrote:
Tue Jan 03, 2023 12:43 pm
* Understanding physics is not a prerequisite to using them, ala a baby doesn't have understand "inverted pendulums" nor "shifting pivot points" in order to walk on two feet.
SNIP
Good points, @TallGrass, sorry I only saw this now!



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GrimSurfer
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Re: Physics debate

Post by GrimSurfer » Sun Jan 15, 2023 12:30 pm

If only we could ski every waking moment of our lives for a period of 3-4 years (which is about how long it takes from first steps to starting to master bipedal locomotion), then this analogy might work better.

Oh, and human evolution has a million years to predispose us to walking. Skiing? Maybe not so much. LOL
We dreamed of riding waves of air, water, snow, and energy for centuries. When the conditions were right, the things we needed to achieve this came into being. Every idea man has ever had up to that point about time and space were changed. And it keeps on changing whenever we dream. Bio mechanical jazz, man.



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TallGrass
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Re: Physics debate

Post by TallGrass » Sun Jan 15, 2023 4:00 pm

GrimSurfer wrote:
Sun Jan 15, 2023 12:30 pm
If only we could ski every waking moment of our lives for a period of 3-4 years (which is about how long it takes from first steps to starting to master bipedal locomotion), then this analogy might work better.
Who else wants to see GrimSurfer cobble together some 3-Pin boots and teensy-tiny cable bindings?

Doesn't have to be perfect -- just look at the flex in the ski boots he made...
Image

... and lack of waterproofness in his try at pak boots! If only he had more snow to work with...
Image


See 1:29



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