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# Bullet Proof Short Turns - PMTS - Video - Page 25

Quote:
 Originally Posted by michaelA Looking carefully at the LeMaster image we see a clue to what really happens - and the Bright Green arrow points right at it.http://Ronlemaster.com/images...maier --- The Resultant Force Vector (Green arrow) is a Result of the two other Vectors (Blue and Yellow). If we take away the skier’s entire structural support with a sudden and complete retraction of both legs - we lose the Green Arrow. We’ve no Blue Arrow since the centripetal/centrifugal force thing is now gone, so there's no Green Arrow needed. The Yellow Arrow wins by default and takes over (gravity).
The blue vector is the lateral component of the inertial path of the CM. The yellow vector is the vertical component of the inertial path of the CM. The green vector is the snow reaction force. When the skier is in balance it resolves into a lateral and vertical component that are of equal magnitude but opposite direction to the green and yellow components. That is why you do not fall down or over.

If you "all of a sudden" somehow lose contact with this snow reaction force, you will begin falling straight along that green line as you go to ground.

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Rick,

While not wishing to be a Dissident... I'll still dissent and stick to my guns on this one.

Hobbit examines the idea based on a skier skiing on one ski with good reason. Doing so eliminates all the confusion that two-footed antics bring into the mix. Evaluating this idea I too stuck with the one-legged skier scenario.

Nap time fast approaches if I want to get up there to ski tomorrow - so I'll have to respond more fully tomorrow...

...but consider...

Does a bent ski deep down in its Carving Rut instantly *unbend* just because we reduce some of the pressure on it?

In my view, the typical soft-flexing ski will maintain its current bend (on a typical groomed surface) so long as sufficient pressure remains to hold it down inside its rut.

The amount of pressure on it from Gravity and CF during a typical turn might easily exceed that required to maintain such pressure. Reducing pressure by some fraction of that overkill would not affect the curving path of the ski, and not reduce centripetal force.

Moreover, *unbending* takes time and distance to occur. Yet the path of our CM will change instantly in the described scenario even if we disavow the idea of a Soft-Ski retaining its turn.

BTW: What of my assessment on the exact direction/path the CM will travel if the BoS is instantly removed? Does that work or not work for you? (not sure after reading your response).

I certainly agree that so long as either ski is in contact with the snow it is affecting the path of our CM. I posted quite a bit on that idea in the threads about 'Tracks' by Heluva a while back. But if our BoS goes away entirely and instantly - which way will the CM go if at Apex in the turn?

.ma
Hey now, don't you guys be keeping me up all night!

BigE,
More thoughts tomorrow, but consider this:
If the skier is going Faster around the same Radius Turn, does that Blue line get bigger, and thereby change the size and direction of the Green arrow?

What if the skier goes really fast around that same turn? Doesn't that Green line aim even more outside?

No matter how big that Blue line gets, no matter how close the Green line gets to it - what direction will the skier's CM go if they lose the turn instantly? Some direction related to one of those two lines - or in the direction of the Tangent to the turn that existed at the moment of release?

.ma
It happened to Hermann in Nagano, he followed the blue line, I think.

....Ott
I thought I could stay out of this too. But no,,,,

Quote:
 No matter how big that Blue line gets, no matter how close the Green line gets to it - what direction will the skier's CM go if they lose the turn instantly? Some direction related to one of those two lines - or in the direction of the Tangent to the turn that existed at the moment of release?
If a skier loses their turn instantly, the two forces then acting on the skier are their inertia and gravity. These two take the skier in that tangent you mentioned, but also down to the snow. Gravity is always there, puling us down towards the snow and we always have our inertia as we move forward, no matter what direction, but in my mind inertia is a straight line. Ski turns a take a secondary disturbing force (centripetal) to change the direction of the skier. Remove it (centripetal force) and we are back to a straight line.

Herman followed the blue line because he got ejected from the turn by over pressuring the ski combined with the surface falling away from under him. It took a little while for gravity to overcome the ejection.
Quote:
 Originally Posted by Uncle Louie I have been asking to SEE this over and over in truly steep narrow terrain carved or not. I was at Vail 2 weeks ago skiing trees in about knee deep powder and came upon an area about 6-8 feet wide, pitch in the high 30's somewhere and about 60' long with nowhere to really escape at the end. I stood there for quite awhile trying to figure out how to ski it without active leg steering and came up empty. I've been at this skiing thing awhile and am at a loss to figure out how to do this w/o active leg steering. I'm here to learn just as many of you are....but this one has me stumped.
1. If you have soft enough skis that the snow can bend them, they will be decambered just by having your weight applied at the middle and the snow resisting along the entire length. The ski is acting like a beam supported by a single column in the middle with a load along its entire length, only upside down.

2. If you do not tip the skis they go forward as in plan view the skis look some what like this || , but if you then tip (not rotate) the decambered skis to the right they will look like this ((. That will turn you.

3. Softer skis will decamber more than stiffer skis. Heavier skiers, and greater speeds will decamber the skis more. Finding a rhythm will allow you to dynamically load and unload the skis, causing a greater decamber in the turn and straightening them at transition.

If you are trying to get your SGs down that run you can still turn them without applying direct rotary through your suffering joints by digging in your tips and letting the snow grab your tips and having the slope apply the rotation for you as you lift the tails, but you had better have a good reason for being there with your race skis.:
The blue line has the downhill direction built in. Resolve the blue line into "fall-line" and "perpendicular to fall-line" vectors changes nothing. It does however, allow you to see how much in the downhill direction the skier would fall once the base of support vanishes.
Quote:
 Originally Posted by Si UL, I am only responding about this since you specifically quoted me. Otherwise I've been trying to remain an observer on this. I think you've seen a close equivalent of this with the video of HH and Max skiing relatively steep bumps without turning out. While I'm not sure about this, I think you've commented that you see steering while these guys claim they have no active input for foot/ski rotation. Having had a little experience with the progression for the BPST I understand where they are coming from. I think I also understand where you are coming from. Whether this discrepancy is based solely on a difference of perceptions, truly different technique, or something else seems to remain unresolved within this this thread on Epic (but certainly not on the PMTS forum!). My own personal perceptions and experience are that it is quite feasible to ski the type of terrain you are talking about without actively trying to rotate (vs. tip) my feet. Do I achieve this all the time? - Absolutely not. However, when I do achieve it I feel more control, flow, and ease than any other time.
So let me ask you this SI, do you see a different physiological mechanism at work in foot first tipping versus foot first steering? In other words, if the intent is down at the feet, are not both utilizing the kinetic chain from the perspective that is closest to the snow?

Secondly, neither tipping nor steering the feet in isolation is very effective on a long straight leg. Add in flex in the lower joints and both become much more effective, add in a lot of flex and the recruitment patterns eventually become the same, depending on the edge angle of the skis in the snow and how much energy it takes to overcome the ski/snow interaction. So the it might just be that the more we flex our lower joints the more our foot tipping movements create rotary forces to the ski, all other things being equal.

I wrote paper on this several years ago on Paragon after some self discovery. Later I was at a boot fitting seminar with a certified pedorthist who told the crowd the same thing. He relate this to one of the reasons the boot industry was moving towards more upright boots, and why we need to address this issue in our own boots. In my mind DavidM's whole premise leads us there also. Food for thought anyway.
Quote:
 Originally Posted by michaelA Late to the party - and I see it's degrading into another snowball fight... but wanted to get back to something posted earlier. I’ll probably get into trouble for it - but I’m with Hobbit on the Flexing Causes Crossover thing. --- In a general sense the skier who Flexes BOTH legs will not fall directly down the Resultant Force Vector line - instead, they'll initiate a crossover (if they do nothing else). Looking carefully at the LeMaster image we see a clue to what really happens - and the Bright Green arrow points right at it.http://Ronlemaster.com/images...maier --- The Resultant Force Vector (Green arrow) is a Result of the two other Vectors (Blue and Yellow). If we take away the skier’s entire structural support with a sudden and complete retraction of both legs - we lose the Green Arrow. We’ve no Blue Arrow since the centripetal/centrifugal force thing is now gone, so there's no Green Arrow needed. The Yellow Arrow wins by default and takes over (gravity). In this case the skier’s CM will ‘plummet’ to the snow via Gravity alone. They’ll do so along a Ballistic path dictated by the instantaneous tangent to the existing turn at the moment of ski/snow release. The fall of their CM will be in the Plane of the Yellow Arrow and will be totally unrelated to the Green Arrow. (The CM's path will curve downward in that plane based on the forward speed of the skier) --- In real life the typical skier uses ‘retraction’ but not usually to the extent described above. The typical skier who Flexes aggressively (retraction) generally keeps their skis on the snow surface. If they do, then mere Flexion does indeed initiate a crossover. The Green Arrow in the image points directly at the cause of this crossover: The still-engaged ski. When we Flex during a turn we relieve support of our CM against both Gravity and Centripetal Force. Meanwhile, our ski (still supported by the snow against both Gravity and Centripetal Force) continues to turn under us. Essentially, our feet (BoS) will continue to move (say left) while our CM takes a slightly straighter path (to the right) than before. Even with a large retraction effort the ski (however slightly weighted) will still diverge its own path in relation to the path of the CM - causing at least a minimal imbalance - which starts the crossover. The slower we Flex, the more the imbalance we create (the ski has more time to deviate under our CM). This occurs regardless what speed we are traveling - but at slower speeds (and on two legs of support) it’s far harder to detect/perceive. .ma PS: Nice posts Hobbit! When people present a thoughtful and well-reasoned dissent to a generally accepted idea it’s always reason enough for me to re-evaluate the idea using their reasoning to see if I can reach their same conclusions. If I can… then it’s time to rebuild my own thinking on the idea.
This image shows half the forces acting on the skier in a frame of reference that moves with the skier. It shows a centrifugal force and a gravity force, the combination of which adds up to the green arrow. The blue line is the x-component of that total force and the yellow one is the Y-component of that force. Yes if the snow is flat, all of the blue line comes from gravity, but it need not be so.

The other half is the reaction force of the snow acting on the skier at the ski. It is exactly equal to the green force, but in the opposite direction. This reaction force makes the net force on the skier zero, and keeps the skier where he is with respect to the frame of reference (F=Ma=0).

Remove the support, and you remove the force of the snow acting on the skier, and the skier is no longer stable, but now accelerates in the direction of the green arrow (a=F/M)

Really all this talk about OLR, ILE, etcetera is fine for figuring out what's going on, but when I ski, I use both.

Retracting both legs completely causes the cm to follow the green arrow.
Retracting the old outside leg while allowing a bit of force to go through the inside ski causes the path of the cm to more horizontal. How much force to put on the inside leg and when depends on where you want the cm to be and when you want it to be there.

The skis and the cm need not follow the same path. You can retract the legs enough to have you cm almost free, but enough weight still on the skis for them to maintain their arc a little longer. You can keep enough weight on them to allow them to cut cleanly right up to, and right after transition. The amount of pressure pushing down on the snow can also be balanced between the two skis in a blend (bad word to PMTS skier) old outside leg retraction and old inside leg extension to manage your rotation about an axis pointing in the forward direction.

PS. I sometimes unweight without pivoting too : (though I'm too much of an old wreck to pivot without unweighting).
A body in motion tends to stay in motion unless it is acted on by an external force. That means when you remove the base of support, the skier moves in the same direction he was moving before he lost his support. That is, tangent to whatever arc he is on. This is not in the same direction as those vectors. The centrepetal force in particular is aligned perpendicularly to the line of travel. The only remaining force on the skier is gravity (which is aligned vertically, also not in the same direcction as the velocity of the skier), so the skier also accelerates straight down.
This whole thread only reinforces my belief that all the detailed technical talk that some instructors indulge in is not only unnecessary, most of it os probably flat wrong.

BK

BK
Quote:
 Originally Posted by BigE The blue line has the downhill direction built in. Resolve the blue line into "fall-line" and "perpendicular to fall-line" vectors changes nothing. It does however, allow you to see how much in the downhill direction the skier would fall once the base of support vanishes.
The blue line to me shows the turn radius direction. Reverse the arrow and you will find the center of the arc of the turn. Release the turn forces and the skier will simply go straight on a tangent somewhere between the skis direction of travel and the blue line.
Quote:
 ...relax the old outside leg and tip into the new turn over the old inside leg,,,
I am having a hard time imagining a universe where this works, Rick.

BTW, Ghost, I agree with your statement about not needing to choose between ILE and OLR--we can do both and probably do a good percentage of the time.
Quote:
 Originally Posted by RicB The blue line to me shows the turn radius direction. Reverse the arrow and you will find the center of the arc of the turn. Release the turn forces and the skier will simply go straight on a tangent somewhere between the skis direction of travel and the blue line.
I was just about to delete my post, since there is an unbalanced downhill component, otherwise, he'd be standing still.
Quote:
 Originally Posted by Bode Klammer I haven't read a single correst answer about that vector diagram (I admit I may not have read them all), so I will tell you the right answer. A body in motion tends to stay in motion unless it is acted on by an external force. That means when you remove the base of support, the skier moves in the same direction he was moving before he lost his support. That is, tangent to whatever arc he is on. This is not in the same direction as those vectors. The centrepetal force in particular is aligned perpendicularly to the line of travel. The only remaining force on the skier is gravity (which is aligned vertically, also not in the same direcction as the velocity of the skier), so the skier also accelerates straight down. This whole thread only reinforces my belief that all the detailed technical talk that some instructors indulge in is not only unnecessary, most of it os probably flat wrong.
Bode Klammer,
Congratulations on mastering Newtons 1st law of motion.

Newton's second law of Motion states that a body will accelerate in the direction of the unbalanced force - the green arrow.

You are partially correct though. The path taken by the skier without the support in plan view can be see to be tangential to the curve. The diagram however is made with reference to a skier in a curve. The tangential path to someone traveling in the curve is a centrifugal path at the moment of release.
Quote:
 Originally Posted by RicB The blue line to me shows the turn radius direction. Reverse the arrow and you will find the center of the arc of the turn. Release the turn forces and the skier will simply go straight on a tangent somewhere between the skis direction of travel and the blue line.
The skis line of travel is irrelevant once they are off the snow. The center of mass is what needs to be considered. The tangent to its direction of travel is perpendicular to a vector directed to the center of the arc of the turn. And to be precise, the blue vector is only directed to the center of the arc in the horizontal plane. The skier may also be arcing in other planes as well, depending on the shape of the surface.
This is now officially unbelievable. I gave you the right answer and you still got it at least half wrong!

BK
Quote:
 Originally Posted by Ghost Newton's second law of Motion states that a body will accelerate in the direction of the unbalanced force - the green arrow.
Once the base of support is lost, the only remaining force is gravity, the yellow line.

Quote:
 Originally Posted by Ghost You are partially correct though. The path taken by the skier without the support in plan view can be see to be tangential to the curve. The diagram however is made with reference to a skier in a curve. The tangential path to someone traveling in the curve is a centripetal path.
Centripetal means directed to the center. The tangent is perpendicular to that. I've never heard the term "centripetal path," probably because an object acted on by centripetal forces cannot possibly follow that path.
Your own explanation is contradictory and ridiculous. Accordiing to yu, in plan biew, the path follows the tangent, but in other planes it follows the green vector. But the green vector has a component (its largest component) in the plane of the plan view, so why does the path not move toward the green vector in that plane, if it does on other planes? Answer me that, physics boy.
I am completely correct, and you get an F.

BK
Quote:
 Originally Posted by BigE I was just about to delete my post, since there is an unbalanced downhill component, otherwise, he'd be standing still.
There is an unbalanced downward force and an unbalanced centrifugal as shown in the diagram without the support. The forces acting on the skier through the ski-snow interface balance the shown forces so that the skier IS standing still - relative to the frame of reference which is moving along a curve. Take away the support and the skier is no longer in the curve, but accelerates toward the outside of the curve and down.

Please someone with software draw another free body drawing in a frame of reference fixed to the Earth, with a cenrtipetal force applied horizontally by the skis (equal and opposite to the blue line), a weight force (the yellow arrow), and an upward force applied by the skis (equal and opposite to the blue line) that makes the skier accelerate towards the centre of the arc.
Quote:
 Originally Posted by Bode Klammer Centripetal means directed to the center. The tangent is perpendicular to that. I've never heard the term "centripetal path," probably because an object acted on by centripetal forces cannot possibly follow that path. I am completely correct, and you get an F. BK
My mistake, I meant centrifugal. I will edit the original. Centrifugal means fleeing the centre, which the blue arrow certainly does.
Quote:
 Originally Posted by Rick ...relax the old outside leg and tip into the new turn over the old inside leg,,,
Quote:
 Originally Posted by nolo I am having a hard time imagining a universe where this works, Rick.
Nolo, you've got to be kidding. : Explain yourself. You used to understand this. I think you still do. This is 101 balance stuff.
Quote:
 Originally Posted by Ghost My mistake, I meant centrifugal. I will edit the original. Centrifugal means fleeing the centre, which the blue arrow certainly does.
Regardless, centripetal and centrifugal are parallel. And both are perpendicular to tangential, which is the path an object will follow when the forces acting on it are released.

BK
Quote:
 Originally Posted by Bode Klammer Centripetal means directed to the center. The tangent is perpendicular to that. I've never heard the term "centripetal path," probably because an object acted on by centripetal forces cannot possibly follow that path. Your own explanation is contradictory and ridiculous. Accordiing to yu, in plan biew, the path follows the tangent, but in other planes it follows the green vector. But the green vector has a component (its largest component) in the plane of the plan view, so why does the path not move toward the green vector in that plane, if it does on other planes? Answer me that, physics boy. I am completely correct, and you get an F. BK
No. You get a D, and I'm being generous.

The object will accelerate in the direction of the green arrow without the support. (edit: note the green arrow is pointing down and to the outside of the curve, not tangential)

What you missed was that the motion of the object is being explained using a frame of reference that moves in a circular path. Switching between frames of reference is tricky, but you might be able to do it.

Imagine you are driving your convertible car around a curve of fixed radius, and you have an inky ball bearing Held in place at the centre of a sheet of graph paper on a flat horizontal surface in the back seat. The graph paper is fixed to your car. As you go around the corner you release the ball bearing. The path of the ball bearing as filmed from an overhead camera on a light pole will be tangential to the curved path the car follows. The path of the ball bearing traced on the graph paper will be quite different.
Rick, either you have an inside where you meant to have an outside or you have an old where you meant to have a new in that sentence. It makes no sense as it reads now, to me anyway:
Quote:
 relax the old outside leg and tip into the new turn over the old inside leg
Quote:
 Originally Posted by Bode Klammer The skis line of travel is irrelevant once they are off the snow. The center of mass is what needs to be considered. The tangent to its direction of travel is perpendicular to a vector directed to the center of the arc of the turn. And to be precise, the blue vector is only directed to the center of the arc in the horizontal plane. The skier may also be arcing in other planes as well, depending on the shape of the surface. This is now officially unbelievable. I gave you the right answer and you still got it at least half wrong! BK
Easy BK. The skis are relevant when they are on the snow as you said, and they give a good reference of the direction of travel "before" they are removed from the snow, which is relevant to the direction of the COM before release, but certainly not exact. Don't make this more complicated than it needs to be.
Quote:
 Originally Posted by nolo Rick, either you have an inside where you meant to have an outside or you have an old where you meant to have a new in that sentence. It makes no sense as it reads now, to me anyway:
How about, "Release you old outside leg and your cm comes over both skis and tips them, and as it goes over the old inside leg and ski this ski becomes the new outside ski"
Thank you, Ghost. I understand what he was trying to say now.
That ball bearing tracing on the graph paper at the moment of release is straight along the radius of the curve. Before release the ball bearing was "stationary" as far as the graph paper was concerned.

The picture with the vector diagrams uses a frame of reference that moves "with the skier", like the graph paper in the car.
Quote:
 Originally Posted by Ghost No. You get a D, and I'm being generous. The object will accelerate in the direction of the green arrow without the support. (edit: note the green arrow is pointing down and to the outside of the curve, not tangential) What you missed was that the motion of the object is being explained using a frame of reference that moves in a circular path. Switching between frames of reference is tricky, but you might be able to do it. Imagine you are driving your convertible car around a curve of fixed radius, and you have an inky ball bearing Held in place at the centre of a sheet of graph paper on a flat horizontal surface in the back seat. The graph paper is fixed to your car. As you go around the corner you release the ball bearing. The path of the ball bearing as filmed from an overhead camera on a light pole will be tangential to the curved path the car follows. The path of the ball bearing traced on the graph paper will be quite different.
Remind me never to let you put up the B fences for the Super G.
1. The green arrow is a reaction to the the centripetal force created at the base of support. If you remove the base of support, the green vector becomes zero. " the green vector is reduced to zero" is just another way of saying "remove the base of supprt" or "relax the outside leg." That vector is irrelevant to the motion of the skier once it is removed.
2. All those vectors are force vectors, not velocity vectors. Velocity after release will be determined be the initial veloctiy and gravity, which is the only remaining force.
3. Regardless of the frame of reference of the forces, the discussion of motion here is from the point of view of the camera, that is, stationary. Does the skier fall down? or does the earth rush up to him?
Since you persist in your error, you are dismissed from class. You will not graduate. You are destined for menial jobs in the food service industry, or even worse, you may be forced to work as a ski instructor to indulge your related compulsions to ski and to talk about vectors without making sense.

Professor Klammer
Quote:
 Originally Posted by RicB Easy BK. The skis are relevant when they are on the snow as you said, and they give a good reference of the direction of travel "before" they are removed from the snow, which is relevant to the direction of the COM before release, but certainly not exact. Don't make this more complicated than it needs to be.
the skis are not a precise reference to use for the motionof the center of mass, particularly if we are trying to determine which way the skier will fall when the base of supprtis removed. In common terms, we are anly trying to determine where the skier will fall, and in most cases that is a situation caused by the skis gooing an a direction different from the direction of the skier. Once you add vector diagrams, you need to be precise. If you don't need to be precise, "the skier falls down" pretty much covers it.

BK
Quote:
 Originally Posted by RicB So let me ask you this SI, do you see a different physiological mechanism at work in foot first tipping versus foot first steering? In other words, if the intent is down at the feet, are not both utilizing the kinetic chain from the perspective that is closest to the snow? Secondly, neither tipping nor steering the feet in isolation is very effective on a long straight leg. Add in flex in the lower joints and both become much more effective, add in a lot of flex and the recruitment patterns eventually become the same, depending on the edge angle of the skis in the snow and how much energy it takes to overcome the ski/snow interaction. So the it might just be that the more we flex our lower joints the more our foot tipping movements create rotary forces to the ski, all other things being equal. I wrote paper on this several years ago on Paragon after some self discovery. Later I was at a boot fitting seminar with a certified pedorthist who told the crowd the same thing. He relate this to one of the reasons the boot industry was moving towards more upright boots, and why we need to address this issue in our own boots. In my mind DavidM's whole premise leads us there also. Food for thought anyway.
RicB, Let me start out by saying I'd classify myself as agnostic on these issues (whatever that means : ). From there then, I'd answer your first question by saying that I do see different physiological mechanisms (muscle activation, recruitment patterns) for tipping vs. twisting of the ski. However, I would add that I don't think these are totally independent, that is, the recruitment patterns may overlap (to a lesser or greater extent depending on the situation).

Furthermore, I have never seen anything published on the nature of the relationship between tipping and twisting (applying a rotary force to the ski in the plane of the ski) based on objective quantitative assessment and study, although I expect there are motion analysis models out there that could do so. Maybe DavidM's stuff has some relationship but I gave up on his writing long ago. Most of what we hear in this regard are people's own impressions, MA "experts" who make very different claims about video and photo montages that are analyzed, people who follow ATS, PMTS, ... gospel. None of these are convincing to me as there are clearly multiple interpretations for the same situations and without more data (perhaps the most important would be to have EMG or other muscle activation data, the second most important probably being sensors for measuring the human/ski interaction) I remain agnostic.

My present thinking is that a fairly exclusive focus on tipping movements as prescribed by PMTS probably is the most effective for most people. That's because (as you've stated) it provides for adequate hip and subsequently foot rotation to at least follow the ski (and perhaps in some situations actively guide the ski . I don't understand the need to individually identify and focus on twisting the foot and ski and blend this with tipping as some here advocate. Sure there are times where I use more twisting, but if I have the balance and skills to employ the tipping movements and skills I strive toward, I think that twisting, when necessary, can be easily (and pretty automatically) produced without much effort at all. I certainly face this necessity regularly in my skiing based upon my level of skill, the terrain I ski, and the speeds I employ.

Now, if you or anyone else can guide me to measurement based published studies on the relationship of recruitment patterns for tipping and twisting a ski I am very interested. For myself, however, I feel like it may be a moot point for the reasons presented above.
Quote:
 Originally Posted by Bode Klammer the skis are not a precise reference to use for the motionof the center of mass, particularly if we are trying to determine which way the skier will fall when the base of supprtis removed. In common terms, we are anly trying to determine where the skier will fall, and in most cases that is a situation caused by the skis gooing an a direction different from the direction of the skier. Once you add vector diagrams, you need to be precise. If you don't need to be precise, "the skier falls down" pretty much covers it. BK
Well we can all agree that the skier will fall where the inertia and gravity take them. Like I said in post 725.
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