Rotation and Counter Rotation

Walt wrote in message ...

Well, congratulations are in order, I suppose. Walking in the
footsteps of Stein Erickson, are we?.

No inverted aerials or funny fanny wiggles for me, Walt. Besides, I
don't have the wavey hair (or much hair of any style), and have no
desire to be any sort of supervisor, let alone a director of skiing.

"lal truckee" wrote in message
news:bqumuu$269j7e$1@ID-

Anyway, Foot2foot, all I was saying was that an outside observer easily
sees what you alude to - the skier cg must be inside the curve in a
turn; however, depending on sophistication, the skier himself could
easily consider himself outside the curve if he identifies
inside/outside by his localize force vector.

There's no way *anyone* could think their body
is on the outside of the skis if they're paying attention
to it. It's when they lose track of it that they fall.
Or, when they get thrown to the outside of the skis
by catching an edge or some such.

Or, in many many cases, the skier doesn't think
about it *at all* or even realize it's necessary because
no one at all ever told them. They think if you move
your knees and your hips and twist your leg, that's
all there is to it.

I'm beginning to wonder how many times you're going
to continue to do this as long as I keep saying that
you need to have your body on the right side of the skis
to turn right.

But you could do me a favor. In this particular case,
you could explain exactly what "localize force vector"
means to you.

The angulation that
provides the sense of being outside that vector is easiely observed in
modern racers: (also note how strongly angulated they are, even today)

As I stated earlier in the thread, this is the "long bone"
technique as opposed to the short bone. Using the hips
instead of the knees. Right? This isn't getting any less
prevalent it's getting more prevalent.

I can not consider how the skier pictured could
*possibly* consider himself on the left side of the skis
as he is turning right.

I'm also really beginning to think I should dump
this thread and start another, but you'd probably
only pull the same thing again.


http://www.audi.com/imgs/com/en/expe...ts/audifisskiw
orldcup/audifisskiworldcup/106760977560732423.jpg
or
http://tinyurl.com/y37m

foot2foot wrote:
"lal truckee" wrote in message
news:bqumuu$269j7e$1@ID-

Sorry we're not communicating.

But you could do me a favor. In this particular case,
you could explain exactly what "localize force vector"
means to you.
CLIP
I can not consider how the skier pictured could
*possibly* consider himself on the left side of the skis
as he is turning right.

The skier is to his right of the gravity vector extending vetically from
his left ski's edge. His cg is at his belly button, between his bib #9
and crotch. His force vector which defines his local "apparent vertical"
extends from his cg to the inside edge of his left ski. A person's
"apparent vertical" provides his local (dynamic) reference for up and
down; gravity provides only one component of the vector addition -
dynamic forces provide the other components.

The skier in the jpeg's right hip is "inside" his apparent vertical, his
head (where his perception is located) is "outside" his apparent
vertical. Since a local "apparent vertical" is all the skiers perceives,
he could easily consider his perception location as "outside" the turn;
it has nothing to do with the gravity defined vertical, which the skier
cannot sense while turning.

We got off on this tangent because you are talking about something else
- a skier's cg must be to the inside of a turn wrt the local gravity
vertical. I agree. All I was saying is it isn't as simple when the frame
of reference is riding along with the skier. Then the definitions change.
Sorry for the confusion.

Carry On, Regardless. (1961)


http://www.audi.com/imgs/com/en/expe...ts/audifisskiw
orldcup/audifisskiworldcup/106760977560732423.jpg

or
http://tinyurl.com/y37m

lal_truckee wrote:
foot2foot wrote:
"lal truckee" wrote in message
news:bqumuu$269j7e$1@ID-

Sorry we're not communicating.

Non-inertial reference frames are in the eye of the beholder.

Furthur...

-klaus