Physics debate

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wabene
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Re: Physics debate

Post by wabene » Tue Jan 03, 2023 8:11 am

I will say all this has got me really thinking about that binding and I understand it better now. A beginner, I went out the other day in more difficult conditions to practice turns and face planted many times. A very nice exfoliation :lol: . Next time I'll bring the cable and now I feel like I could adjust the tension with purpose and understanding.

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Verskis
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Re: Physics debate

Post by Verskis » Tue Jan 03, 2023 8:11 am

tkarhu wrote:
Tue Jan 03, 2023 7:18 am

Thanks for the conversation, and patience all seem to still have some. I ski NNN-BC only, but think I now after reading understand what a cable would do. It lets a skier to lean forward against the spring without falling on one’s nose. Further, that lets you edge your rear ski more.

So @GrimSurfer seems to be right that the binding does nothing. It lets a skier do things. Well that is quite obvious actually. Yet for a skier a binding feels active, when it actually just returns some energy you put on it. Would it help further conversations here, if GS would use the concept of active binding in same meaning how most others use it here? That would not be necessary technically, but would certainly clarify & help human communication.
In NNN-BC the flexor does exactly the same job as the cable and springs; it allows the skier to apply torque to the ski, in other words push against the ground with the front part of the ski.

Binding itself does nothing, that's true. It needs a source of energy to load that spring. Once the spring is loaded, it will exert force until it returns to the original state.
In a static situation, the spring is not doing any work (since work is force x displacement, and the displacement is zero in a static situation), but it is always applying force when the boot heel is lifted, even if the boot stays stationary (in a lifted position).



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Verskis
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Re: Physics debate

Post by Verskis » Tue Jan 03, 2023 8:14 am

mca80 wrote:
Tue Jan 03, 2023 8:09 am
Verskis wrote:
Tue Jan 03, 2023 12:12 am
My education has included quite a lot of physics (Master of science in technology). How about you?
The argument from authority is a logical fallacy. Not to say you don't know what you're talking about, but whether or not one holds X Y and Z degrees is irrelevant to a proposition's truth or falsehood.
That is true, my degree does not mean I am always right. That was just a response to Grimsurfer when he suggested that I need to consult somebody who has actually studied physics.



mca80
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Re: Physics debate

Post by mca80 » Tue Jan 03, 2023 8:26 am

Verskis wrote:
Tue Jan 03, 2023 8:14 am
That is true, my degree does not mean I am always right. That was just a response to Grimsurfer when he suggested that I need to consult somebody who has actually studied physics.
I know, I was just being a smartass ;) For what it's worth (nothing, in my estimation), my degree was in philosophy.

Reading through this thread, albeit tedious and hand-wringingly frustrating at times, has been quite helpful. Beginning to think I made a bad move putting nnnbc on Kongsvold to try and learn tele turns with leather boots.



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TheMusher
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Re: Physics debate

Post by TheMusher » Tue Jan 03, 2023 8:37 am

More about normal force and how normal forces are not constant during a jump (nor on the ski through a telemark stance) - as you compress your weight and
953D625F-845E-4012-B278-E378DA5BF332.png
This obviously also explains why Olympic skiers need to exercise deadlift more than most athletes - and it is not only to generate momentum by weight..



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GrimSurfer
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Re: Physics debate

Post by GrimSurfer » Tue Jan 03, 2023 8:42 am

mca80 wrote:
Tue Jan 03, 2023 8:26 am
Reading through this thread, albeit tedious and hand-wringingly frustrating at times, has been quite helpful. Beginning to think I made a bad move putting nnnbc on Kongsvold to try and learn tele turns with leather boots.
wabene wrote:
Tue Jan 03, 2023 8:11 am
I will say all this has got me really thinking about that binding and I understand it better now. A beginner, I went out the other day in more difficult conditions to practice turns and face planted many times. A very nice exfoliation :lol: . Next time I'll bring the cable and now I feel like I could adjust the tension with purpose and understanding.

This is superb… and I’m not just talking about @Verskis diagrams and very clear explanations, which were terrific.

The conversation has never been about proving anyone living right or wrong. It’s been about thinking about how Newtonian physics applies to skiing (and it does because this branch of physics governs movement). The benefit we derive from this will help us in making good gear choices and analyzing our technique. (I’m still wondering, at times, why I fell. LOL. )

Education or intelligence are irrelevant. The smartest guy in the room was Isaac Newton all along. We were all striving to understand him. Guys and gals at the JPL are doing this today, though on levels that make my mind spin.

The brilliant bit is that this conversation, heated as it was, made us think. It resulted in some folks rethinking their approach to skiing (it wasn’t about who was right and wrong because Newton was right… all of us are just catching up… a few hundred years later. Sheesh… what an amazing dude.).

There is a brilliance, and beauty, to letting human interaction run its course. And we’ve all been part of that here.

@Stephen brought some calm and order. @fisheater mentioned metatarsals… which got me thinking about pressure points beyond merely the sole (which is just a big blob of rubber). @Roelant introduced the diagram showing arcs of motion, which got me thinking about tension (beyond just the tension in sprung cables).
Last edited by GrimSurfer on Tue Jan 03, 2023 9:02 am, edited 4 times in total.
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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TheMusher
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Re: Physics debate

Post by TheMusher » Tue Jan 03, 2023 8:45 am

Verskis wrote:
Tue Jan 03, 2023 8:11 am
tkarhu wrote:
Tue Jan 03, 2023 7:18 am

Thanks for the conversation, and patience all seem to still have some. I ski NNN-BC only, but think I now after reading understand what a cable would do. It lets a skier to lean forward against the spring without falling on one’s nose. Further, that lets you edge your rear ski more.

So @GrimSurfer seems to be right that the binding does nothing. It lets a skier do things. Well that is quite obvious actually. Yet for a skier a binding feels active, when it actually just returns some energy you put on it. Would it help further conversations here, if GS would use the concept of active binding in same meaning how most others use it here? That would not be necessary technically, but would certainly clarify & help human communication.
In NNN-BC the flexor does exactly the same job as the cable and springs; it allows the skier to apply torque to the ski, in other words push against the ground with the front part of the ski.

Binding itself does nothing, that's true. It needs a source of energy to load that spring. Once the spring is loaded, it will exert force until it returns to the original state.
In a static situation, the spring is not doing any work (since work is force x displacement, and the displacement is zero in a static situation), but it is always applying force when the boot heel is lifted, even if the boot stays stationary (in a lifted position).
Think this is a good summary of the mechanics and forces involved.



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wabene
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Re: Physics debate

Post by wabene » Tue Jan 03, 2023 9:09 am

Ok @GrimSurfer I have a question that I intend as a yes or no question. Would you please oblige me with an answer in this fashion?

When the skier flexes the boot and loads the spring cable, does that cable transmit a force?



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GrimSurfer
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Re: Physics debate

Post by GrimSurfer » Tue Jan 03, 2023 9:12 am

wabene wrote:
Tue Jan 03, 2023 9:09 am
Ok @GrimSurfer I have a question that I intend as a yes or no question. Would you please oblige me with an answer in this fashion?

When the skier flexes the boot and loads the spring cable, does that cable transmit a force?
I don’t think it does. I wouldn’t dismiss the possibility entirely, but I’m confident in saying that whatever forces that it could transmit are inconsequential. (Even a wet spaghetti noodle can transmit some force, but nothing of any consequence).

I think it does a credible job in controlling the foot and creating tension that changes the pressure point.
Last edited by GrimSurfer on Tue Jan 03, 2023 9:17 am, edited 1 time in total.
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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wabene
Posts: 715
Joined: Sat Feb 06, 2021 9:53 am
Location: Duluth Minnesota
Ski style: Stiff kneed and wide eyed.
Favorite Skis: Åsnes Gamme, Fischer SB98, Mashus M50, M78, Pano M62
Favorite boots: Crispi Svartsen 75mm, Scarpa T4
Occupation: Carpenter

Re: Physics debate

Post by wabene » Tue Jan 03, 2023 9:14 am

GrimSurfer wrote:
Tue Jan 03, 2023 9:12 am
wabene wrote:
Tue Jan 03, 2023 9:09 am
Ok @GrimSurfer I have a question that I intend as a yes or no question. Would you please oblige me with an answer in this fashion?

When the skier flexes the boot and loads the spring cable, does that cable transmit a force?
I don’t think it does.
Ok, not exactly yes or no but I will gladly take it :lol: . Thanks



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