Talk:Proper velocity

message: 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)
replies: text:  In this context I've added a figure, and an application section on comparing velocities. Thermochap (talk) 18:47, 27 January 2008 (UTC)
replies: text:  I've now also added sections on the disperson curve and proper acceleration apps mentioned above. Thermochap (talk) 15:12, 4 February 2008 (UTC)
thread_title:  some comments on this topic  

message: Hopefully this critique will be taken as constructive rather than just me tossing rocks.
1. Please check me here, I'm just a student of this stuff but I don't think proper velocity is a MEASURED quantity except when the observer is at rest with respect to the map, where it just is velocity. If I'm correct, this eliminates the core explanation found in the lede. My principle objection here is that there is no 'physical' quantity that is not measured by the observer (with respect to his/her coordinate frame). Confusing calculated quantities with measured quantities is confusing theory with 'physical reality'.
2. The first paragraph of the Introduction uses the term "super-relativistic".  I'm not familiar with it. I understand "non-relativistic" and "relativistic", and assume that sub- and super- are synonyms for that.  To me "super-relativistic" implies v > c, and so is non-sense. (Except when talking about possibly, group velocity?)
3. Half of first paragraph of the Introduction is "See Also" and NOT explanatory. It doesn't, imho, belong there ("see also" belongs at the end of any explanatory article, of course)
4. I simply don't understand how proper motion can "reside in a slice" of space-time. The meaning eludes me. How does this distinguish it from any other quantity...don't they all "reside" in a slice of 3-d space??
5. Engineering applications vs coordinate free "insight". I'm lost understanding this. My GUESS is that the underlying claim is something like "its useful for quantitative models, rather than general principles"??
6. Lose the junk on gyrovector rubbish. Its exotic and little used. (does NOT belong in the mainstream explanation)
7. You have a formula which uses |w|².....?? This implies that either you don't know that w² is IDENTICAL to |w|² or that w is complex (if not worse).
8. The same formula defines Betaw as a function of w. I must be missing something. w=gamma*v, right? < dx/dτ  = (dx/dt)(dt/dτ)> but you claim βw = 1/(√(1-(w/c)²)) AND β=1/γ !!! At best this is massively confusing! beta for a given velocity is traditionally 1/γ,  β for a given velocity is defined as √(1-(v/c)²), right? using the same symbol for a different quantity is just terribly confusing. That is: what does βu mean??; is it beta for velocity u or is it βw for some proper velocity u?
Anyway, that's as far as I got in this before I became so confused I decided continuing was pointless.173.189.73.56 (talk) 18:48, 28 July 2014 (UTC)
thread_title:  More comments 

message: If proper velocity eliminates the need for relativistic mass then why is transverse Mass different from longitudinal Mass?
Just granpa (talk) 07:19, 1 July 2016 (UTC)
replies: text: Article talk pages are for discussions about the article, not about (aspects of) the subject—see wp:Talk page guidelines. You can ask at the wp:Reference desk/Science. Good luck. - DVdm (talk) 08:30, 1 July 2016 (UTC)
thread_title:  longitudinal Mass