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 Exercise [19.16] a 
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Joined: 12 Jul 2010, 07:44
Posts: 154
Post Exercise [19.16] a
Roberto posted his solution as "b" because Laura already had a solution posted up on her website.

For reference, you can find Laura's solution here: http://camoo.freeshell.org/19.16.pdf

However, I'd like to point out that there's a significant error in it:

Laura says
"the volume acceleration is the Lie derivative of the 3-volume element wrt the acceleration vector a^c = w^bR_{0b0}^c."

Ignoring the fact that w^b is not defined anywhere, you simply can't get an acceleration by taking a first derivative (Lie or otherwise). You need to take the derivative twice!

...take a look at my solution ([19.16] c) for what I think Penrose had in mind here.

29 Apr 2012, 08:23
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