jmfbahciv@aol.com wrote:

In article <445e64ad.12647836@news.west.earthlink.net>,
bw@barrrk.net (B1ackwater) wrote:

Human balance is a DYNAMIC act - a thousand minor corrections
to our position a minute.

Sure. And the detection devices are the toes coordinated
with the inner ear turbulence.

Requires energy, requires a fair amount
of brain quietly dedicated to the task. We're always teetering
on the brink of collapse. A quick push or a few slow gin fizzes
and we're back to all fours again.

That's why beer is better.

Heh. This reminds me of the interesting demonstrations of the human
balance mechanism performing under extreme conditions I have witnessed.
Normally we seem to stay very close to a fully poised condition or
else fail catastrophically -- a few quick stabs or emergency arm
flailing forming the fleeting intermediate states. But I've seen a
drugged person fall in slow motion, never quite contacting the ground
with anything but their feet, and yet keeling over at such alarming and
bizarre angles and attitutes that you are absolutely certain it is
physically impossible for them not to fall in another microsecond --
and then, incredibly, somehow pull themselves back into an upright
posture! And not once, but repeatedly. This system has ranges of
motion beyond our usual experience.

On Sat, 29 Apr 06 10:52:58 GMT,

In article <44535138$0$22380$ed362ca5@nr1.newsreader.com>,
"Glen M. Sizemore" <gmsizemore2@yahoo.com> wrote:

"r norman" <NotMyRealEmail@_comcast.net> wrote in message
news:fif4525kjth59n1m9vrmbon12h6vmfv9bv@4ax.com...

On 28 Apr 2006 08:59:09 -0700, "neo" <AbheJet@gmail.com> wrote:

Suppose there is human statue of cement in standing position. We human
being can remain in standing position. But why can't this statue remain
standing even if it is exact like our body?

Of course a human statue can stand. There are many examples around
the world!

You probably mean "why can't a human statue not firmly attached
stand?" It can, statically. However any small horizontal force, like
the wind, will tend to topple it. We react by contracting muscles to
shift our balance for small forces and by moving the position of our
feet for larger forces. When the forces get strong enough, we fall
over. Statues have a very difficult time responding to outside
disturbances so either their feet are firmly fixed to the ground or
they fall over much more easily than we do.

When it was discovered that movement of (disembodied) parts of animals
could
be induced by electricity it became clear that the soul infused the
entire
animal, not just the brain. Perhaps a soul could be infused throughout a
concrete statue and it would be able to stand. Perhaps that is what
allowed
Pinocchio to move about even though he was not a "real boy."

I sure hope you are an 8-year-old child.

So you think that, if it moves, it has a soul. Do clouds
have one?

In the spirit of Glen's post, of course not. Clouds do not have "one"
soul, each cloud has its own!

I'm somebody who has become an expert in minimizing energy output.
I'll guarantee that standing still takes more energy.

In article <6%w4g.28$15.4874@news.uchicago.edu>,
mmeron@cars3.uchicago.edu wrote:

In article <20060429060034.P54826@emu.uq.edu.au>, Timo Nieminen

<uqtniemi@mailbox.uq.edu.au> writes:

On Sat, 28 Apr 2006, PD wrote:

neo wrote:

Suppose there is human statue of cement in standing position. We human
being can remain in standing position. But why can't this statue remain
standing even if it is exact like our body?

There are two types of equilibrium: stable and unstable. Both are
slope=0 points in a potential energy curve, but one curves up and the
other curves down. A standing human is better modeled with unstable
equilibrium.

Why? We stand with our centre of mass over our feet, which constitute a
platform of finite extent, and thus the equilibrium is stable unless a
perturbation is sufficiently large.

I can recall reading some stuff about how miraculous the act of standing
up is, with continual corrections required, but the main things are that
the CoM is over the feet (and hence forward of the ankles), and the torque
about the ankles is balanced by the elasticity of the Achilles
tendon/calves. Nature has "chosen" a simple rubber-band based model over
some complex computer-controlled continual correction model - hardly a
surprise.

Indeed, Mother Nature designs well. Moreover (just anticipating what
you say next), the system is designed for moving, not standing. Other
than in some highly contrived social situations (ceremonies and the
like) there is hardly ever a call for standing motionless for longer
than few minutes.

With periodic small corrections, an unstable equilibrium
can be maintained, but a statue cannot make those corrections.

Of course, humans move, and take advantage of moving the CoM out of the
stable region when we walk. I've heard it said that walking (at what
speed?) on flat ground uses less energy than standing (is this true?).

Try standing at attention for an hour. Then walk for an hour.
Compare how it feels. I'm not sure that more energy is used in the
first case, overall, but you certainly end up more tired.

I'm somebody who has become an expert in minimizing energy output.
I'll guarantee that standing still takes more energy.

A picture
of a kangaroo suddenly pops into my head with the efficiency
of moving using a small bounce. So that must imply springs
where part of the KE also stores PE for the next jump.

OTOH, another hypothesis is that standing still involves fighting
the spin of the Earth. It takes a lot of effort to stay on the
edge of a merry-go-round.

On Fri, 28 Apr 2006

Timo Nieminen <uqtniemi@mailbox.uq.edu.au> writes:

On Sat, 28 Apr 2006, PD wrote:

neo wrote:

Suppose there is human statue of cement in standing position. We human
being can remain in standing position. But why can't this statue remain
standing even if it is exact like our body?

There are two types of equilibrium: stable and unstable. Both are
slope=0 points in a potential energy curve, but one curves up and the
other curves down. A standing human is better modeled with unstable
equilibrium.

Why? We stand with our centre of mass over our feet, which constitute a
platform of finite extent, and thus the equilibrium is stable unless a
perturbation is sufficiently large.

I can recall reading some stuff about how miraculous the act of standing
up is, with continual corrections required, but the main things are that
the CoM is over the feet (and hence forward of the ankles), and the torque
about the ankles is balanced by the elasticity of the Achilles
tendon/calves. Nature has "chosen" a simple rubber-band based model over
some complex computer-controlled continual correction model - hardly a
surprise.

Indeed, Mother Nature designs well. Moreover (just anticipating what
you say next), the system is designed for moving, not standing. Other
than in some highly contrived social situations (ceremonies and the
like) there is hardly ever a call for standing motionless for longer
than few minutes.

If you need to "stand" for a long time, it's usually easiest to lie down.

One past housemate of mine was very, very lazy. I came home from work one
day and saw he was lying down on the sofa to watch TV. I asked him why,
and he said sitting up made him too tired. The only exercise
he ever got was sitting on the sofa to watch TV, and walking to the
kitchen for food or to the toilet. So I told him that he'd better sit up,
or else he'd reach the stage where even lying down to watch TV would make
him tired. The plasticity of the human body.

With periodic small corrections, an unstable equilibrium
can be maintained, but a statue cannot make those corrections.

Of course, humans move, and take advantage of moving the CoM out of the
stable region when we walk. I've heard it said that walking (at what
speed?) on flat ground uses less energy than standing (is this true?).

Try standing at attention for an hour. Then walk for an hour.
Compare how it feels. I'm not sure that more energy is used in the
first case, overall, but you certainly end up more tired.

I don't doubt that efficient walking (exactly what that might be?) is
easier than standing; the easiest walk is a controlled fall. I wonder how
fast one needs to walk to use more energy than standing? I'd just also add
that standing at attention is not a very natural way to sand.

Some measurements were made of energy used by quadrapeds - mammals vs
reptiles - in walking and running. The researchers were surprised to find
that lizards were more efficient than mammals, since everybody knows that
mammals are vastly more advanced than reptiles. But reptiles move side to
side, while mammals move up and down and need to do work against gravity.
Kangaroos are about as efficient as reptiles because they store this
energy elastically and get it back when they spring back up, but other
mammals are less efficient.

Efficiency isn't the only thing that's important - why cars don't have
Stirling engines!

On Fri, 28 Apr 2006

Timo Nieminen <uqtniemi@mailbox.uq.edu.au> writes:

On Sat, 28 Apr 2006, PD wrote:

neo wrote:

Try standing at attention for an hour. Then walk for an hour.
Compare how it feels. I'm not sure that more energy is used in the
first case, overall, but you certainly end up more tired.

I don't doubt that efficient walking (exactly what that might be?) is
easier than standing; the easiest walk is a controlled fall. I wonder
how fast one needs to walk to use more energy than standing? I'd just
also add that standing at attention is not a very natural way to sand.

Some measurements were made of energy used by quadrapeds - mammals vs
reptiles - in walking and running. The researchers were surprised to
find that lizards were more efficient than mammals, since everybody
knows that mammals are vastly more advanced than reptiles. But reptiles
move side to side, while mammals move up and down and need to do work
against gravity. Kangaroos are about as efficient as reptiles because
they store this energy elastically and get it back when they spring back
up, but other mammals are less efficient.