Re: Mechanical, chemical and heat energy

[Truman Prevatt <truman.prevatt@netsrq.com>]

Niccolai Murphy wrote:

 

No they are not spherical but can be approximated into a number of
basic shapes, cylinders for barrel and limbs, ellipse for neck and an
ovoid for the head. In most cases you are down to a radius and length
or at least a mjor and minor axis. So the equations still hold true,
you can't get around them with a bit of arm waving. Compensation for
the decrease in surface area to weight ratio is generally species
specific, hence the large ears on the African elephant and so forth. I
think we agree on that part so on to the next...
 

You can estiamte the curvature tensor of the surface of a horse by how
much tangent plains "wiggle"   There are large ares where the
tangent plain doesn't wiggle too much if at all.  And of course there
are places where it wiggles a lot.  If one took the mass density of
a horse and put it into the volum of the sphere, the radius - call it R
- would be quite small compaired to the size of a horse.  The curvature
of a sphere is 1/R, here R is the radius.  There are large areas where
the curvature of the horse is close to zero much less than 1/R and places
where it was much greater than 1/R.

Footnote... I thought most animals were not sperical because they
couldn't stop themselves fro rolling out of bed otherwise.
 

There is some truth to that.

\

Yes, 10 or 15% sounds like it might be but right. However if we
consider the unloaded horse and if we consider the system of the horse
alone, then the heat generated by the horse through damping losses in
the mechanism, we could in general approximate the heat generated to
the weight of the horse. Damping approximates to the product of force
and velocity. With force prportional to weight and velocity held
constant that leaves the heavier guy with more heat to loose.
 

Yes an unloaded 500 kg horse will produce more heat than an unloaded 400
kg hours.But a loaded 400 kg horse carring 100 kg will produce as much
heat as an unloaded 500 kg horse and will have a smaller surface area in
which to dissipate the heat.

The mechanism of damping I'm assuming here is the damping in muscle,
skeleton and joints. All quite wastefull, why didn't nature invent the
wheel and paved roads?

> At any point the larger horse of the same shape will have additional
> surface in which to dissipate heat.

True, but will also have more heat to disipate.

Not  if the total amount of work to be performed is the same. If my wife carried a back pack to make her weight equal to mine and I carryied no pack and we climbed to the top of West Marron Pass, she would have as much heat to dissipate as me.  Now when I tell her that I weight more than she and that the pack didn't matter and she should be happy, well I'll let someone else tell here this.

That is why I carry the heavest pack.  I tried the above argument on her several years ago and still have a bump on my head.

 

I agree that there is a beautiful control loop in a horse. Consider.
>From a energy consumption point of view damping is very important in a
mechanical system controlled or otherwise. If you clap a horse on the
rump (with a few noticable exceptions, I'm tempted to say Arabs here
but that wouldn't be PC so I'll say my TWH mare) it will not go
bouncing off the walls forever. It will deform slightly where you
impacted it and the muscle/fat will bounce back once and the come to
rest. QED... Damping. There's tons of it in the system and just as
well too. I'm sure the control loop minimizes the losses as far as
possible. I think you have considered heat only from chemical sources
and not mechanical ones too.

Oh hell I'll say it.  Arabs will go into undamped oscillation from
time to time.  In fact Arabs have numerious unstable equilibria. 
This probably has more do with the resonance cavity between the ears where
the brain goes on other breeds <G>.

 
 

Well we could try, as a first approxmation consider two spheres, with
masses M1 and M2, S for displacement then, stick dot S into the
damping term and dot dot S into the forcing function.... by the time
we are done we could design the ultimate saddle pad!
 

And saddle.

==
Nicco Murphy - Poway, San Diego, CA
 

--
Truman Prevatt
Brooksville, FL

Mystic “The Horse from Hell” Storm
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Jordy a.k.a. Bridger (when he is good)
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