An analysis of the canonical ice skater:

https://phys.libretexts.org/Bookshelves/Classical_Mechanics/Variational_Principles_in_Classical_Mechanics_(Cline)/12%3A_Non-inertial_Reference_Frames/12.08%3A_Coriolis_Force

I don't dispute his analysis, though his notation and
presentation is awful.

However, I don't accept his conclusion: the chemical
muscle energy which withdraws the arms, eventually
stores as kinetic energy in the flywheel (the skater).

--
Rich

On Thursday, May 4, 2023 at 2:46:11 PM UTC-7, RichD wrote:
> An analysis of the canonical ice skater:
>
> https://phys.libretexts.org/Bookshelves/Classical_Mechanics/Variational_Principles_in_Classical_Mechanics_(Cline)/12%3A_Non-inertial_Reference_Frames/12.08%3A_Coriolis_Force
>
>
> I don't dispute his analysis, though his notation and
> presentation is awful.
>
> However, I don't accept his conclusion: the chemical
> muscle energy which withdraws the arms, eventually
> stores as kinetic energy in the flywheel (the skater).
>
> --
> Rich

It reduces the angular moment?

It sort of seems like that force for "f = ma" is to be a derived quantity
instead of a defined quantity, about things like "m/s or s/m, which
one should be, velocity or inverse velocity" about the changes in
units over time, over time.

It's like in a system of potentials, that, the potential increases,
then, it sort of "runs out" instead of "builds up".

I.e., in a theory where "it's sum potentials what are real and
the classical is inverted", it's a thing.

I put it in these terms because you can't really hear "centrifugal"
when "the pail-experiment has a centripetal force", that there
only is a "true centrifugal" in the "sum of potentials".
There's a usual ambiguity of centrifugal and centripetal.
Then also "Coriolis" is another, "force", here that otherwise
expresses exchanging potential energy the lever moment of
the arm for the potential energy the angular bit.

It's kind of like framing it in a "sum-of-histories" for path integral,
that "sum-of-potentials" is real.

In Einstein's Out of My Later Years he looks at a sort of
attack on classical motion for his total field theory, ...,
I sort of frame that in terms of: "Newton's Zero'eth laws".

This is about where "bringing to motion" and "coming to rest"
are two different things: yes I know that's separate or extra
the usual notion they are same.

On Friday, May 5, 2023 at 6:29:46 PM UTC-7, Ross Finlayson wrote:
> On Thursday, May 4, 2023 at 2:46:11 PM UTC-7, RichD wrote:
> > An analysis of the canonical ice skater:
> >
> > https://phys.libretexts.org/Bookshelves/Classical_Mechanics/Variational_Principles_in_Classical_Mechanics_(Cline)/12%3A_Non-inertial_Reference_Frames/12.08%3A_Coriolis_Force
> >
> >
> > I don't dispute his analysis, though his notation and
> > presentation is awful.
> >
> > However, I don't accept his conclusion: the chemical
> > muscle energy which withdraws the arms, eventually
> > stores as kinetic energy in the flywheel (the skater).
> >
> > --
> > Rich
> It reduces the angular moment?
>
> It sort of seems like that force for "f = ma" is to be a derived quantity
> instead of a defined quantity, about things like "m/s or s/m, which
> one should be, velocity or inverse velocity" about the changes in
> units over time, over time.
>
> It's like in a system of potentials, that, the potential increases,
> then, it sort of "runs out" instead of "builds up".
>
> I.e., in a theory where "it's sum potentials what are real and
> the classical is inverted", it's a thing.
>
> I put it in these terms because you can't really hear "centrifugal"
> when "the pail-experiment has a centripetal force", that there
> only is a "true centrifugal" in the "sum of potentials".
> There's a usual ambiguity of centrifugal and centripetal.
> Then also "Coriolis" is another, "force", here that otherwise
> expresses exchanging potential energy the lever moment of
> the arm for the potential energy the angular bit.
>
> It's kind of like framing it in a "sum-of-histories" for path integral,
> that "sum-of-potentials" is real.
>
> In Einstein's Out of My Later Years he looks at a sort of
> attack on classical motion for his total field theory, ...,
> I sort of frame that in terms of: "Newton's Zero'eth laws".
>
> This is about where "bringing to motion" and "coming to rest"
> are two different things: yes I know that's separate or extra
> the usual notion they are same.

I really like how in the next section the author gets into the Routhian,
which helps a lot to explain the potentials and oscillating in these things..

When I was a kid my dad had a dog, it was Butch,
it was an English Springer Spaniel, and really got around,
he trained it one thing, when he went "Babe Ruth",
it bayed "Routh".

RichD <r_delaney2001@yahoo.com> wrote:

> An analysis of the canonical ice skater:
>
> https://phys.libretexts.org/Bookshelves/Classical_Mechanics/Variational_Pr
> inciples_in_Classical_Mechanics_(Cline)/12%3A_Non-inertial_Reference_Frame
> s/12.08%3A_Coriolis_Force
>
>
> I don't dispute his analysis, though his notation and
> presentation is awful.
>
> However, I don't accept his conclusion: the chemical
> muscle energy which withdraws the arms, eventually
> stores as kinetic energy in the flywheel (the skater).

What's your problem? You don't accept energy conservation?
Or angular momentum conservation?
Or that force is required to pull in those arms?

Jan

On Sunday, May 7, 2023 at 2:43:15 AM UTC-7, J. J. Lodder wrote:
> RichD <r_dela...@yahoo.com> wrote:
>
> > An analysis of the canonical ice skater:
> >
> > https://phys.libretexts.org/Bookshelves/Classical_Mechanics/Variational_Pr
> > inciples_in_Classical_Mechanics_(Cline)/12%3A_Non-inertial_Reference_Frame
> > s/12.08%3A_Coriolis_Force
> >
> >
> > I don't dispute his analysis, though his notation and
> > presentation is awful.
> >
> > However, I don't accept his conclusion: the chemical
> > muscle energy which withdraws the arms, eventually
> > stores as kinetic energy in the flywheel (the skater).
> What's your problem? You don't accept energy conservation?
> Or angular momentum conservation?
> Or that force is required to pull in those arms?
>
> Jan

Don't you know that work is involved to hold out the arms?

Don't you know that energy is exchanged?

Don't you know that potential angular momentum is exchanged?

It's kind of like you'll do anything for a dollar,
a medium of exchange.

On May 7, J. J. Lodder wrote:
>> An analysis of the canonical ice skater:
>> https://phys.libretexts.org/Bookshelves/Classical_Mechanics/Variational_Principles_in_Classical_Mechanics_(Cline)/12%3A_Non-inertial_Reference_Frames/12.08%3A_Coriolis_Force
>
>> However, I don't accept his conclusion: the chemical
>> muscle energy which withdraws the arms, eventually
>> stores as kinetic energy in the flywheel (the skater).
>
> What's your problem? You don't accept energy conservation?
> Or angular momentum conservation?
> Or that force is required to pull in those arms?

What happens at the end of the pull?

Retracting the arms injects kinetic energy, from the muscles.
The author's claim is that this eventually adds to the total
rotational energy, as the arms merge with the torso.

But the arms end up crashing into her hips, they HALT
(radially) at that point. Their kinetic energy goes into heat.
They continue to rotate with her body, but that's merely the
remnant of their initial energy, which they contained while outstretched.

The human body is too complex. Try a rotating platform, with a ball
attached to the rim. A golfer standing at that point strokes a putt
straight at the center.

The ball rolls radially. And, the floor has tangential static friction,
such that the ball continues to rotate with the platform, at the
same angular speed as the platform. Thus, seen from the center,
it rolls straight in; an external inertial observer sees it follow a spiral path.

The ball eventually drops into the hole... then what? Does it revolve around
the center? Does its linear kinetic convert into rotational energy? That's silly.
It bounces off the walls, then settles. The energy dissipates as heat.

--
Rich

On Monday, May 8, 2023 at 1:04:01 PM UTC-7, RichD wrote:
> On May 7, J. J. Lodder wrote:
> >> An analysis of the canonical ice skater:
> >> https://phys.libretexts.org/Bookshelves/Classical_Mechanics/Variational_Principles_in_Classical_Mechanics_(Cline)/12%3A_Non-inertial_Reference_Frames/12.08%3A_Coriolis_Force
> >
> >> However, I don't accept his conclusion: the chemical
> >> muscle energy which withdraws the arms, eventually
> >> stores as kinetic energy in the flywheel (the skater).
> >
> > What's your problem? You don't accept energy conservation?
> > Or angular momentum conservation?
> > Or that force is required to pull in those arms?
> What happens at the end of the pull?
>
> Retracting the arms injects kinetic energy, from the muscles.
> The author's claim is that this eventually adds to the total
> rotational energy, as the arms merge with the torso.
>
> But the arms end up crashing into her hips, they HALT
> (radially) at that point. Their kinetic energy goes into heat.
> They continue to rotate with her body, but that's merely the
> remnant of their initial energy, which they contained while outstretched.
>
> The human body is too complex. Try a rotating platform, with a ball
> attached to the rim. A golfer standing at that point strokes a putt
> straight at the center.
>
> The ball rolls radially. And, the floor has tangential static friction,
> such that the ball continues to rotate with the platform, at the
> same angular speed as the platform. Thus, seen from the center,
> it rolls straight in; an external inertial observer sees it follow a spiral path.
>
> The ball eventually drops into the hole... then what? Does it revolve around
> the center? Does its linear kinetic convert into rotational energy? That's silly.
> It bounces off the walls, then settles. The energy dissipates as heat.
>
>
> --
> Rich

Kinetics and kinematics are different,
kinetics essentially linear,
kinematics about moments and rotation,
in terms of rigid bodies and deformable bodies.

The study of billiards is quite a regular tableau.

The "pail-experiment" usually is introduced with
the difference between the perspective of the
centrifgual and the perspective of the centripetal.

Energy is the usual system of units and for the
dimensional analysis, but it's about the exchange
and the interchange, that motion is motion but
it's always from acceleration/deceleration, exchange.

The potential and the potential and the potential,
basically make for the classical that the matters of
pespective allow information to direct work and
effect classical action and the machination of work.
(Advantage of intelligence and organization versus entropy.)

This is that the field theory is always potentials about
the continuity equations or "what equals zero", about
the additive identity and multiplicative identity and
annihilator, about continuity laws implementing conservation laws,
and about potential theory implementing classical theory.