Physics debate

This is the World Famous TelemarkTalk / TelemarkTips Forum, by far the most dynamic telemark and backcountry skiing discussion board on the world wide web. We have fun here, come on in and be a part of it.
User avatar
GrimSurfer
Posts: 638
Joined: Sun Dec 11, 2022 11:56 am
Ski style: Nordic Backcountry
Favorite Skis: Yes
Favorite boots: Uh huh

Re: Physics debate

Post by GrimSurfer » Mon Jan 02, 2023 11:03 am

wabene wrote:
Mon Jan 02, 2023 10:50 am
The real question is how can something as magical as surfing be grim? We may have an answer :lol:
And maybe wabene really is the “font of knowledge”. :D

Here’s the thing though… people do things all the time without actually thinking about how or why things work the way they do. A lot is taken for granted.
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.

User avatar
CwmRaider
Posts: 610
Joined: Wed May 15, 2019 6:33 am
Location: Subarctic Scandinavian Taiga
Ski style: XC-(D) tinkerer
Favorite Skis: Åsnes FT62 XP, Børge Ousland
Occupation: Very precise measurements of very small quantities.

Re: Physics debate

Post by CwmRaider » Mon Jan 02, 2023 11:33 am

This sketch from Monty Python comes to mind. Perhaps most of you know it already but it cracks me up every time.



User avatar
connyro
needs to take stock of his life
needs to take stock of his life
Posts: 1233
Joined: Mon Jan 26, 2015 11:46 am

Re: Physics debate

Post by connyro » Mon Jan 02, 2023 12:15 pm

GrimSurfer wrote:
Mon Jan 02, 2023 11:03 am

Here’s the thing though… people do things all the time without actually thinking about how or why things work the way they do. A lot is taken for granted.
Do you really think most competent telemark skiers take telemark skiing mechanics for granted? Do you ski using telemark turns? Do you distribute your weight evenly between your skis? Do you weigh and carve with your trailing ski or does it just sort of follow the lead ski and skid around? Why do some telemark bindings feature selectable pivot points (Axls, Hammerheads)? I suspect that if you were competent at telemark technique, you would not be so ready to discount what the rest of us experience when executing telemark turns. It may make the most sense for you to trot your argument out at a physics forum and see if you can get any traction there for your ideas and then report back here what you found out. According to your logic, telemark technique is superfluous and we should all be skiing alpine technique on our freeheel setups.



User avatar
GrimSurfer
Posts: 638
Joined: Sun Dec 11, 2022 11:56 am
Ski style: Nordic Backcountry
Favorite Skis: Yes
Favorite boots: Uh huh

Re: Physics debate

Post by GrimSurfer » Mon Jan 02, 2023 12:35 pm

connyro wrote:
Mon Jan 02, 2023 12:15 pm
GrimSurfer wrote:
Mon Jan 02, 2023 11:03 am

Here’s the thing though… people do things all the time without actually thinking about how or why things work the way they do. A lot is taken for granted.
Do you really think most competent telemark skiers take telemark skiing mechanics for granted? Do you ski using telemark turns? Do you distribute your weight evenly between your skis? Do you weigh and carve with your trailing ski or does it just sort of follow the lead ski and skid around? I suspect that if you were competent at telemark technique, you would not be so ready to discount what the rest of us experience when executing telemark turns. It may make the most sense for you to trot your argument out at a physics forum and see if you can get any traction there for your ideas and then report back here what you found out. According to your logic, telemark technique is superfluous and we should all be skiing alpine technique on our freeheel setups.
I am not questioning anyone’s skiing. I’m sure everyone here is a world class skier.

I’m merely pointing out that people may not have a complete understanding of the interaction of forces that are occurring when they are executing textbook lines in perfect powder on 3 pin bindings with a cable.

Do they have an intuitive understanding of how to ski? Sure. Likely better than mine. But this doesn’t make, by extension, what they write about how force operates valid.

Some of the more quotable quotes that illustrate this include:

“ I don't think "heel control" is even a thing.” (A statement made, on a telemark forum without anyone objecting. LOL)

“ Pressuring the skis has nothing to do with friction or gravity.” (IDK where to start with this one… ROFL)

I don’t see much to be gained in highlighting exactly who wrote these things. Not here to embarrass anybody. Just pointing out that, as a community of interest, we might all benefit from a bit of careful thought on how stuff works.

Just like we can all go to a hill or trail and benefit from practice on how we can make the stuff we ski on work for us.

I’d do the latter but, atm, there’s no snow. At least none that is skiable after several days of rain.
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.



User avatar
connyro
needs to take stock of his life
needs to take stock of his life
Posts: 1233
Joined: Mon Jan 26, 2015 11:46 am

Re: Physics debate

Post by connyro » Mon Jan 02, 2023 12:46 pm

GrimSurfer wrote:
Mon Jan 02, 2023 12:35 pm
connyro wrote:
Mon Jan 02, 2023 12:15 pm
GrimSurfer wrote:
Mon Jan 02, 2023 11:03 am

Here’s the thing though… people do things all the time without actually thinking about how or why things work the way they do. A lot is taken for granted.
Do you really think most competent telemark skiers take telemark skiing mechanics for granted? Do you ski using telemark turns? Do you distribute your weight evenly between your skis? Do you weigh and carve with your trailing ski or does it just sort of follow the lead ski and skid around? I suspect that if you were competent at telemark technique, you would not be so ready to discount what the rest of us experience when executing telemark turns. It may make the most sense for you to trot your argument out at a physics forum and see if you can get any traction there for your ideas and then report back here what you found out. According to your logic, telemark technique is superfluous and we should all be skiing alpine technique on our freeheel setups.
I am not questioning anyone’s skiing. I’m sure everyone here is a world class skier.

I’m merely pointing out that people may not have a complete understanding of the interaction of forces that are occurring when they are executing textbook lines in perfect powder.

Do they have an intuitive understanding of how to ski? Sure. Quite possibly better than mine. But this doesn’t make, by extension, what they write about how force operates valid.

Some of the more quotable quotes that illustrate this include:

“ I don't think "heel control" is even a thing.” (A statement made, on a telemark forum without anyone objecting. LOL)

“ Pressuring the skis has nothing to do with friction or gravity.” (IDK where to start with this one… ROFL)

I don’t see much to be gained in highlighting exactly who wrote these things. Not here to embarrass anybody. Just pointing out that, as a community of interest, we might all benefit from a bit of careful thought on how stuff works.

Just like we can all go to a hill or trail and benefit from practice on how we can make the stuff we ski on work for us.
thanks for answering my questions. Lol. Since you won't answer, I'll make assumptions and the big assumption is that you dont understand telemark skiing and your grasp of critical thinking is suspect. You seem most interested in feeling superior on a public forum and least interested in actual telemark skiing which is what most of us do here, regardless of being "world class skiers" or not.



User avatar
Stephen
Posts: 1487
Joined: Thu Aug 06, 2020 12:49 am
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 » Mon Jan 02, 2023 12:49 pm

After so many pages I would love to see a concise recap of the point or points that are being discussed / debated.
Is it about controlling lateral movement of the back end of the ski boot (the heel)?
Is it about whether or not a free heel binding is able to apply additional force to the part of the ski in front of the boot toe?
Something else?
Thanks.



User avatar
GrimSurfer
Posts: 638
Joined: Sun Dec 11, 2022 11:56 am
Ski style: Nordic Backcountry
Favorite Skis: Yes
Favorite boots: Uh huh

Re: Physics debate

Post by GrimSurfer » Mon Jan 02, 2023 12:59 pm

connyro wrote:
Mon Jan 02, 2023 12:46 pm
GrimSurfer wrote:
Mon Jan 02, 2023 12:35 pm
connyro wrote:
Mon Jan 02, 2023 12:15 pm


Do you really think most competent telemark skiers take telemark skiing mechanics for granted? Do you ski using telemark turns? Do you distribute your weight evenly between your skis? Do you weigh and carve with your trailing ski or does it just sort of follow the lead ski and skid around? I suspect that if you were competent at telemark technique, you would not be so ready to discount what the rest of us experience when executing telemark turns. It may make the most sense for you to trot your argument out at a physics forum and see if you can get any traction there for your ideas and then report back here what you found out. According to your logic, telemark technique is superfluous and we should all be skiing alpine technique on our freeheel setups.
I am not questioning anyone’s skiing. I’m sure everyone here is a world class skier.

I’m merely pointing out that people may not have a complete understanding of the interaction of forces that are occurring when they are executing textbook lines in perfect powder.

Do they have an intuitive understanding of how to ski? Sure. Quite possibly better than mine. But this doesn’t make, by extension, what they write about how force operates valid.

Some of the more quotable quotes that illustrate this include:

“ I don't think "heel control" is even a thing.” (A statement made, on a telemark forum without anyone objecting. LOL)

“ Pressuring the skis has nothing to do with friction or gravity.” (IDK where to start with this one… ROFL)

I don’t see much to be gained in highlighting exactly who wrote these things. Not here to embarrass anybody. Just pointing out that, as a community of interest, we might all benefit from a bit of careful thought on how stuff works.

Just like we can all go to a hill or trail and benefit from practice on how we can make the stuff we ski on work for us.
thanks for answering my questions. Lol. Since you won't answer, I'll make assumptions and the big assumption is that you dont understand telemark skiing and your grasp of critical thinking is suspect. You seem most interested in feeling superior on a public forum and least interested in actual telemark skiing which is what most of us do here, regardless of being "world class skiers" or not.
Your fight is with Isaac Newton… or maybe the Royal Society. It’s not with me. Really, it isn’t.
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.



User avatar
connyro
needs to take stock of his life
needs to take stock of his life
Posts: 1233
Joined: Mon Jan 26, 2015 11:46 am

Re: Physics debate

Post by connyro » Mon Jan 02, 2023 1:06 pm

GrimSurfer wrote:
Mon Jan 02, 2023 12:59 pm
connyro wrote:
Mon Jan 02, 2023 12:46 pm
GrimSurfer wrote:
Mon Jan 02, 2023 12:35 pm


I am not questioning anyone’s skiing. I’m sure everyone here is a world class skier.

I’m merely pointing out that people may not have a complete understanding of the interaction of forces that are occurring when they are executing textbook lines in perfect powder.

Do they have an intuitive understanding of how to ski? Sure. Quite possibly better than mine. But this doesn’t make, by extension, what they write about how force operates valid.

Some of the more quotable quotes that illustrate this include:

“ I don't think "heel control" is even a thing.” (A statement made, on a telemark forum without anyone objecting. LOL)

“ Pressuring the skis has nothing to do with friction or gravity.” (IDK where to start with this one… ROFL)

I don’t see much to be gained in highlighting exactly who wrote these things. Not here to embarrass anybody. Just pointing out that, as a community of interest, we might all benefit from a bit of careful thought on how stuff works.

Just like we can all go to a hill or trail and benefit from practice on how we can make the stuff we ski on work for us.
thanks for answering my questions. Lol. Since you won't answer, I'll make assumptions and the big assumption is that you dont understand telemark skiing and your grasp of critical thinking is suspect. You seem most interested in feeling superior on a public forum and least interested in actual telemark skiing which is what most of us do here, regardless of being "world class skiers" or not.
Your fight is with Isaac Newton… or maybe the Royal Society. It’s not with me. Really, it isn’t.
No, it's with you. Me and IN are good. Let's try this: since you are the only user in the history of this forum to bring up the term "heel control" (do a search if you don't believe me) , maybe you could explain exactly what that telemark sking term means?



User avatar
Verskis
Posts: 179
Joined: Fri Oct 27, 2017 2:14 am
Location: Tampere, Finland
Ski style: XCD touring on small hills. Heavy tele at resort
Favorite Skis: Åsnes Rabb 68
Favorite boots: Alico Ski March
Occupation: Hydraulics engineer

Re: Physics debate

Post by Verskis » Mon Jan 02, 2023 1:09 pm

fisheater wrote:
Mon Jan 02, 2023 10:43 am
lowangle al wrote:
Mon Jan 02, 2023 9:23 am
We hold these truths to be self evident. Skis can rise in the snow and cables produce tip pressure. If this doesn't jive with some rules of physics, you must be looking at the wrong rules.
Thank you Allen.
The real lesson is don’t wrestle with a pig, you’ll just end up all muddy and the pig likes it.
You can consider me the pig, internet debates on basic physics are fun 😁



User avatar
Verskis
Posts: 179
Joined: Fri Oct 27, 2017 2:14 am
Location: Tampere, Finland
Ski style: XCD touring on small hills. Heavy tele at resort
Favorite Skis: Åsnes Rabb 68
Favorite boots: Alico Ski March
Occupation: Hydraulics engineer

Re: Physics debate

Post by Verskis » Mon Jan 02, 2023 1:12 pm

GrimSurfer wrote:
Mon Jan 02, 2023 10:46 am
Verskis wrote:
Mon Jan 02, 2023 10:27 am
GrimSurfer wrote:
Mon Jan 02, 2023 9:57 am
Quote right. Springs do return the energy put into them. So they can change an impulse (force) curve. But that curve still sums to zero, so there is no additive force. The net force is still the same.

This is what control elements do. They can limit motion, they can regulate force. They don’t multiply force.

Now some would argue that a cable is a lever. This is incorrect. A lever is a *rigid element* with unequal forces at each end rotating around a fulcrum.
I never said that the springs multiply force. But springs return (virtually all) the energy put into them.

Think about the TTS binding (once again, this kind of binding: https://www.voile.com/voile-telemark-te ... -tour.html). If we compare it to your stiff knees, that would mean that there is no spring (cables) in them, but the pins (that are the pivot point) are very rusty and therefore have great friction when the boot is rotated. That means that when the skier would bend the leg and lift the heel, the binding would actually transfer some torque to the ski via frictional forces when the boot is rotating, but once the rotation stops, there would be zero force and zero torque on the binding, as the friction is generating force only when there is moving. The skier would only be able to have some tip pressure during the movement phase, but not at all in a static situation.

However, if we think about a correctly working binding, with virtually frictionless pins and strong springs on the cables, now the energy is stored in the springs, and the loaded springs are able to provide force in the static situation too (when the heel is lifted). No energy is consumed, since nothing is moving, but the springs exert force, equal but opposite, on the binding and the boot. Now this spring force is acting on the lever, which is the binding itself: the length of the lever is the distance between the boot holding pins and the attachment point of the cable. The cable is not a lever, it is only an extension of the spring. As long as the spring is loaded, it is trying to pull the boot heel down, or the binding up. This is what makes both the supporting force on your leg, and the pressure on the ski tip.

When you think about it, there is only two ways to unload that spring: either the boot must come down, or the rear of the binding must come up. So, the spring is trying to make you stand upright again, so it is trying to prevent you from going over the handlebars, while simultaneously it is trying to lift that rear of the binding up, which means that the ski tip would be lowered down, since the fulcrum is on the pins of that binding. That ski tip lowering effect is what people call tip pressure.

I would accept a great deal of what you’re saying… but the issue is that skiing is done with bent knees, bent ankles, flexed metatarsals.

This gets in the way of looking at the ski-binding-boot-skier system as a simple lever. All this bending and dynamic movement is moving mass.

We know that movement can build momentum on flat ground. Leverage won’t do that.

We know that shifting masses either side of normal force (as well as ski edge angle etc), will cause a ski to stop or turn.
But we were not debating how to stop or turn the skis, we were debating on what the heel cable does for the ski.



Post Reply