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At 10:13 AM 3/5/96, Steve VanDevender wrote:
>Kelly Starks writes:
> > >David gave me these numbers
> > >Pluto's mean orbital velocity is 4.74 km/sec.
> > >Earth's mean orbital velocity is 29.79 km/sec.
> > >
> > >Are these right?  They seem backwards.
> >
> > I'ld agree.   It seems odthat you'ld accelerate out from the inner system
> > to a slower velocity.  I suppose you might be losing the dif to potential
> > energy changes.
> >
> > But I suppose it isn't critical for our discusion.  Assumeing a beam
> > diameter 40 times the dimeter of earth.  4.76Km/s will still have you cross
> > the beam in 31 hours.
>This is the paradox of orbital mechanics.  To go from a faster
>smaller-radius circular orbit to a slower larger-radius circular orbit,
>you have to accelerate twice -- once to raise the apoapsis of your
>orbit, again to raise the periapsis.  So, in other words, yes, your
>acceleration goes largely into raising your potential energy rather than
>increasing your speed.
>An elliptical orbit has a higher orbital velocity at periapsis than a
>circular orbit of that radius, and a slower orbital velocity at apoapsis
>than a circular orbit of that radius.
>If orbital velocities got faster and faster the farther out you went,
>how could there be such a thing as escape velocity?  How far out would
>you have to go before orbital velocity got close to the speed of light?
>It really wouldn't make any sense.
>On another note:
>Could we all try to avoid quoting huge amounts of each other's letters
>only to add a few lines of comment?  It's redundant (I swear there are
>now dozens of copies of all the same material from overagressive
>quoting) and also very hard to read, as it requires paging through large
>amounts of stuff we've all read already to get to the few new items of
>comment.  I think it's a good rule of thumb to have less quoted material
>than comments in a reply.

Well it least cut it down to little more then whats nessisary to understand
the comment.



Kelly Starks                       Internet: kgstar@most.fw.hac.com
Sr. Systems Engineer
Magnavox Electronic Systems Company
(Magnavox URL: http://www.fw.hac.com/external.html)