On Wed, 2005-08-31 at 16:40 -0400, Olin Lathrop wrote:
> Herbert Graf wrote:
> > Consider a rocket with a force meter on the nose, and one on the tail,
> > and the rocket is on the earth pointed straight up. On the pad the two
> > meters would differ in reading, since the one on the tail is closer to
> > the earth then the one on the nose.
> 
> Correct in theory, but now figure out the difference in practise, even for a
> large rocket.  The radius of the earth is about 6.38Mm.  Let's say the large
> rocket is 100m tall.  That yields a distance ratio of 1.0000157 between top
> and bottom.  Gravity is proportional to 1/R**2, so the gravity ratio is
> 1.0000314, or about 31ppm.  Measuring accelleration to that accurracy is NOT
> easy.

And, if you had bothered reading my post in this thread PRIOR to this
post you would have seen me say:

"Yes, there is a difference, it's just really hard to measure."

TTYL

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