[Shotimes] Pontiac unveils SHO successor?

[Jason Hartberger]

Well if you want to get overly technical about it, you can't pull a car,
period. The only two things that can "pull" are a magnetic field and the
nucleonic attractions between electrons and protons (also glue, but nobody's
really sure about that yet). Everything else is just pushing - i.e. exerting
force from behind. when you pull a car by its bumper, for example, you curl
your hand around the bumper and your fingers are actually pushing it. Weird
to think about, but true.

The difference in pushing and 'pulling' comes in force vectors. when you are
pushing a single point, the possible force vectors range in a rough
semicircle in front of you, with the semicircle representing the possible
ways what you're pushing will go. This is all assuming one track vector -
i.e. bicycle or something only contacting the ground in one line. With two
track vectors (a car), you have two semicircles centered on each track
vector (wheel), so that when you push a car at its center you're exerting
different (but opposite) angular forces on each track vector. The net result
is the car goes straight. But, since you're pushing it, you get what is
called a divergent force vector progression, which basically means the
faster you go, the less chance that you're going to pick the perfectly
straight line, and there are infinite ways for the car to be (or go) off the
straight line. Any change in the track vectors will be multiplied by this
effect, as is seen when you're pushing an airplane back... the tractor only
turns a little, but the plane just keeps turning more and more as the
track/force vector ratio increases....

When you pull, you get a convergent force vector progression, which means
that differences between the track vector and the force vector will become
zero (as long as you have the necessary mass/energy to offset the mass/speed
of the object you're pulling) as you pull it. Practical applications of this
are abundant... pull a shopping cart that's facing a different direction
than you to see.

So why do people push cars instead of pulling them? There are a couple of
answers - mass/energy differences and human body construction. It takes the
same amount of energy to push or pull something - that's just straight
physics - but humans generally don't possess enough strength to push a car
either hard enough or fast enough to affect divergent track vectors beyond
their control. Remember, track vector amplitude is directly related to input
energy and speed. But on a more practical level - human bodies are meant to
push. We can put our entire weight behind something and push a lot easier
than we can pull the same thing... something about how legs work (I'm into
physics, not biology).

On the other hand, you will never see a tow truck pushing a car. If the
track vector changes even a minute amount related to the force vector, the
results will be catastrophic very very quickly, especially at highway
speeds. Tow trucks and such things pull cars specifically because of the
convergent force vector progression tendency - any change in the track
vector will quickly be cancelled out by the tow truck's own mass and energy.

Everybody got that?

Jason

----- Original Message ----- 
From: "John Stout" <sho_man1@yahoo.com>
To: <shotimes@autox.team.net>
Sent: Wednesday, November 03, 2004 8:44 AM
Subject: RE: [Shotimes] Pontiac unveils SHO successor?


> Easier to push than pull ???  I want to see you Push a log chain, any 
> questions ??
>
> Ron Porter <ronporter@prodigy.net> wrote:Not a relevant example. Pencils 
> don't have wheels or steering.
>
> Try a toy car. No easier to push or pull it.
>
> Better yet, try this. Let's say you are driving with someone, and your car
> dies in the middle lane. Do you push it off the road, or do you pull it 
> off
> the road?
>
> These examples are as irrelevant as a pencil or rope example. I have had
> steep driveways on a few houses, and the only way to get up them in snow
> with the SHO way to drive up backwards.
>
> Ron Porter