ParaNet BBS/propel

ParaNet BBS/propel

File Name:	propel.txt
Author:	Unknown
Date:	Unknown
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Key Words:	ParaNet, UFO, Ufology

(2556)  Thu 14 Nov 91 12:09p
By: Bcrenna@ac.dal.ca
To: All
Re: Non-newtonian Behaviour And Ufos
St: Sent                                                        Reply in  2559
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@UFGATE newsin 1.27
From: bcrenna@ac.dal.ca
Date: 14 Nov 91 00:26:34 GMT
Organization: Dalhousie University, Halifax, Nova Scotia, Canada
Message-ID: <1991Nov13.202634.1998@ac.dal.ca>
Newsgroups: alt.alien.visitors

In article <5884@tamsun.tamu.edu>, n138ct@tamuts.tamu.edu (Brent) writes:
>
> (Somebody else suggests that):
>
>> [... UFOs do things...] such as make right angle
>> turns that would seem to violate Newton's Second Law,
>
> Well, this doesn't necessarily violate any physical laws.  If a car runs
> into a very solid brick wall, it'll usually bounce off, but it basically
> stops.  If the wall was angled to the right or left, the car would merely
> bounce off in that direction - that's the same as UFO's making right
> angle turns.  My point is that given a large enough force (wall), a body
> moving in one direction can be redirected into another direction.
Spacecraft,
> and I'm talking about the Shuttle and other human kinds, move about in space
> using very abrupt movements.  They fire rockets in one direction to rotate
> the craft in another direction, and later fire rockets (by the same amount)
> in the opposite direction to stop rotating.  Both the start and the stop of
> the rotation is abrupt; again, not a violation of any physical laws.
>
>   I guess by saying something seems to "violate Newton's Second Law" adds
> a little mysticism and appeal to the subject...
>
> (deleted)
>
> Well, sure we could ask them.  But that doesn't mean any laws were violated,
>it only means that the craft abruptly turned.

While I agree that the rapid changes in direction ascribed to some UFOs need
not imply a violation of classical mechanics principles, you might also
consider the following:

From simple mechanics, we have the relation
              t
   Impulse = S Fdt = P  - P .  (Sorry, my editor doesn't have an integral
sign.)
              0       f    i

For a massive object travelling at considerable speed, an abrupt change in
direction necessitates a large impulse; that is, either a small force acting
over a relatively long period of time (which is inconsistent with the "abrupt"
idea), or a large force acting over a short time interval (as in your "car and
wall" example.)  From the descriptions of the motions UFOs purportedly display,
it would seem that the acceleration occurs during a very brief time indeed
(say, on the order of milliseconds).  Therefore, a large force must be acting.
Just for fun, suppose an object of mass 500kg travelling at a speed of 100 m/s
reverses direction in a time period of 10 milliseconds (these are probably all
on the conservative side, given what's been described sometimes); we can easily

calculate that the average force acting must be 10 million Newtons:
     _
     F =   Pf - Pi     (-mv) - mv    -(500kg)(100m/s) - (500kg)(100 m/s)
          ---------  = ----------- = ----------------------------------
           tf - ti       tf - ti                 (.01 s)

             7       2
       = - 10  kg m/s ( the "-" indicates it's directed opposite the original
                        motion)

I expect that this value could be increased by an order of magnitude by playing

with the numbers a bit.  I'm not an engineer, but that sounds like a fairly
large force to go exerting on a compact, aerodynamic structure, no matter how
uniformly it's done over the extent of the body (please, correct me if I'm
wrong).
      Of course, I can easily avoid the consideration of applied forces.  I
phrased this in terms of forces only because you did; if we consider the
acceleration in the same example (assuming it's a constant), we
have
            vf - vi       (-100m/s) - (100 m/s)               2
      a = -----------  =  ---------------------   = -20000 m/s  = 2000g
            tf - ti              (.01 s)

Any occupant of the craft would experience an acceleration 2000 times the
gravitational acceleration at the earth's surface, which I expect would neatly
flatten them along the interior walls (or perhaps imbed them into the leading
edge).  So, either the inhabitants are on a phenomenal weight training program,
or nobody's on board and the craft are remarkably constructed to withstand
these accelerations, or there's something rather mysterious about the whole
process, or it isn't actually occurring.
      Thus, no violations of Newtonian mechanics requires some equally mystical
feats of engineering and biomechanics; assuming the craft and occupants are (in
a materials science sense) rather unremarkable, something distinctly
non-Newtonian is going on.  Unless, of course, it isn't occurring in the first
place.
      I apologise if what I've said is too trivial for words, or if I've made
any mistakes; sometimes both the obvious and sarcasm in others eludes me....

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