
In article <58pih2t0t7e9938g0vtdt3k4rsfu6uuess@xxxxxxx>,
Lester Zick <dontbother@xxxxxxxxxxx> wrote:
> On Mon, 25 Sep 2006 16:13:24 0600, Virgil <virgil@xxxxxxxxxxx> wrote:
>
> >In article <anigh21g8i7i8hcru9923ve4rulcf8c9qe@xxxxxxx>,
> > Lester Zick <dontbother@xxxxxxxxxxx> wrote:
> >
> >> On Mon, 25 Sep 2006 12:55:00 0600, Virgil <virgil@xxxxxxxxxxx> wrote:
> >>
> >> >In article <md6gh29aa00pvo1m6jdob8eios0b573ccb@xxxxxxx>,
> >> > Lester Zick <dontbother@xxxxxxxxxxx> wrote:
> >> >
> >> >> On Wed, 20 Sep 2006 10:42:56 0700, Lester Zick
> >> >> <dontbother@xxxxxxxxxxx> wrote:
> >> >>
> >> >> >On 14 Sep 2006 18:47:35 0700, QncyMI@xxxxxxxxxxxx wrote:
> >> >> >
> >> >> >>yeah, prove that geometrically using calculus or
> >> >> >>just algebra . . .
> >> >> >
> >> >> >Where m1 is aggregate gravitationally attractive mass
> >> >> >in a disk of uniform thickness and density in which the
> >> >> >amount of gravitationally attractive matter ~ area=rrpi
> >> >> >times unform thickness d:
> >> >> >
> >> >> >As a function of radius r the aggregate force of gravitational
> >> >> >attraction will be:
> >> >> >
> >> >> >F=Gm1m2/rr=Gm1(rrpi)m2/rr=Gm1(pi)m2 and
> >> >> >
> >> >> >dF/dr=0 and gravitationally attractive force is constant as a function
> >> >> >of radius r: hence tangential velocity of all m2's will remain
> >> >> >constant as a function of radius r.
> >> >> >
> >> >> >QED.
> >> >>
> >> >> I think that in light of the foregoing the appropriate question to ask
> >> >> is not why the velocity curve in Andromeda is flatter than expected
> >> >> but why the velocity curve in Andromeda is not flat to begin with?
> >> >
> >> >Because "F=Gm1m2/rr=Gm1(rrpi)m2/rr=Gm1(pi)m2" is based on some false
> >> >assumptions, among others, that any part of Andromeda further from the
> >> >center than r has no effect.
> >>
> >> That's your false assumption not mine.
> >
> >The whole of that equation and how it applies to Andromeda are Zick's
> >assumptions, not mine.
>
> Not quite. I don't assume it applies to Andromeda; you do.
Not me. I know quite well that it does not apply to Andromeda.

