Talk:Four-acceleration

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the four acceleration as only equal to the proper velocity within that insantaneously comoving frame. outside of that it is not equal to it. proper acceleration is a*gamma^3 where a is coordinate acceleration. Em3ryguy (talk) 18:34, 25 September 2008 (UTC)[reply]

Is the second expression correct? I think a gamma factor of the space coordinates got lost between the first and the second expression ... --84.152.236.51 (talk) 23:11, 26 September 2009 (UTC)[reply]