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 Error in the 4-velocity 
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Joined: 26 Mar 2010, 04:39
Posts: 109
Post Error in the 4-velocity
I believe there are problems with the 4-velocity vector defined on page 435 and 436. I think Penrose made the error in the definition because the metric he is using is not the usual one.

See my response to Exercise 18.18 for more details.

Please let me know if you agree/disagree.


18 Jun 2010, 10:48

Joined: 12 Jul 2010, 07:44
Posts: 154
Post Re: Error in the 4-velocity
Robin, I think you are correct.

It should be:

v_\alpha v^\alpha = c^4

and

v^\alpha = \gamma c^2 (1,\mathbf{v})

on pages 435 and 436 respectively.


...btw it's your answer to Exercise [18.19] not 18.18, that contains those corrections.


10 Jan 2012, 16:50
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