Talk:Proper velocity

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I would like this article to be accessible to students of all ages. Did I err on the side to too many words, and too little "equation boilerplate"? Would an example or two of its application help? Thermochap (talk) 14:15, 20 January 2008 (UTC)

It would benefit from an extra opening sentence or two that explains the concept in as simple a language as possible (e.g. avoiding jargon like "flat spacetime") before going on to the more technical definition. So even an absolute beginner in relativity could understand it. You could also mention some authors call proper velocity "celerity".

Somewhere in Wikipedia, whether on this page or somewhere else, could compare and contrast all the various ways of measuring motion: coordinate velocity, proper velocity, rapidity, doppler factor, Lorentz factor. And formulas to convert from any one to any other. --Dr Greg (talk) 12:01, 11 April 2008 (UTC)

A "low-cost" opening concept-wise is a good idea, as is mention of celerity as it gets more technical. The Lorentz factor/rapidity page might be a good place for the overview, given that the latter (albeit more abstract) is a grand meeting ground for all of these velocity parameters. Thermochap (talk) 13:30, 11 April 2008 (UTC)

[edit] some comments on this topic

Equation boilerplate in this case probably adds little to new understanding, so I think the article is a good start. Information on the utility of rapidity's Sinh (along with Cosh as the Lorentz factor and Tanh as coordinate velocity) is helpful for anyone (particularly beginners) wishing to solve high speed problems in context of a single spacetime slice. As in using the metric equation, the only post-Newtonian concept needed to start is that of proper time on the traveling object's clock.

Particle land speed records are more impressive when quoted in lightyears per traveler year (~10⁵c fixed, ~10¹⁰c collider) than in lightyears per map year (~1c). Log-Log plots of Lorentz factor minus one versus proper velocity are particularly interesting. Multiplying one of these by mass yields a family of kinetic energy versus momentum curves that make contact with many branches of everyday and modern physics. Proper velocity also helps put the integrals of constant proper acceleration (for use within a single spacetime slice) into simple form.

It looks like pedagogical examples (worked problems, for instance) are more commonly offered via external links. However added sections should gradually materialize that indirectly serve the purpose of providing more examples. Propervelocity (talk) 17:22, 22 January 2008 (UTC)

In this context I've added a figure, and an application section on comparing velocities. Thermochap (talk) 18:47, 27 January 2008 (UTC)

I've now also added sections on the disperson curve and proper acceleration apps mentioned above. Thermochap (talk) 15:12, 4 February 2008 (UTC)