## Search the FAQ Archives

3 - A - B - C - D - E - F - G - H - I - J - K - L - M
N - O - P - Q - R - S - T - U - V - W - X - Y - Z

# Invariant Galilean Transformations On All LawsSection - 9. But Doesn't x.c'=x.c?

( Single Page )
[ Usenet FAQs | Web FAQs | Documents | RFC Index | Airports ]

Top Document: Invariant Galilean Transformations On All Laws
Previous Document: 8. What does sci.math have to say about x0'=x0-vt?
Next Document: 10. But Isn't (x'-x.c')=(x-x.c) Actually Two Transformations?
```That idea is one of the most idiotic to come up, and it does
so frequently. And in a number of guises.

The idea being that x.c' <> x.c-vt, with x.c being what
we have called x0 above; the notation makes no difference.

Some crackpots have managed to maintain that position even
after graphs have illustrated that such an idea means that
after a while a circle center represented by x.c' could be
outside the circle.

The leading crackpot just make that explicit, as far as
one can tell from his befuddled post in response to a line
about "active" transforms, which are actually moving body
situations, not coordinate transformations:
--------------------------------------------------------------------

e>An active transform is not a coordinate transform, ...

Right, it is a transform of the center (in the opposite direction)
done to effect the change of coordinates without a coordinate
transform.  ...

E: Transform of the center?  Center of a circle?
He really is saying a circle center moves in
the opposite direction of the circle! Right?
--------------------------------------------------------------------

If r=10 and x.c was at x.c=0, then the points on the circle
(10,0), (-10,0), (0,10) and (0,-10) could at some time become
(-10,0), (-30,0), (-20,10), and (-20,-10), but with x.c'=x.c,
the circle center would be at (0,0) still!  The circle is here
but its center is way, way over there! Indeed, although a change
of coordinate systems is not movement of any object described in
the coordinates, the x.c'=x.c crackpottery is tantamount to the
circle staying put but the center moving away. Or vice versa.

```

## User Contributions:

Top Document: Invariant Galilean Transformations On All Laws
Previous Document: 8. What does sci.math have to say about x0'=x0-vt?
Next Document: 10. But Isn't (x'-x.c')=(x-x.c) Actually Two Transformations?

Single Page

[ Usenet FAQs | Web FAQs | Documents | RFC Index ]

Send corrections/additions to the FAQ Maintainer:
Thnktank@concentric.net (Eleaticus)

Last Update March 27 2014 @ 02:12 PM