User talk:Maschen

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Response re: gravitomagenetism[edit]

I responded to you on my talk page. Fresheneesz (talk) 21:58, 29 August 2014 (UTC)

Plea for support in calming things down[edit]

Belated "welcome back"! If you were inclined, you could take a look at the kerfuffle at Talk:Rotation_matrix#Derivation and second my plea for cool-down. I fear an obstreperous contributor needs reminding of WP:TE or WP:NOTGETTINGIT. The issue is a triviality, but I am not sure I don't see an edit war in the making there.... Cuzkatzimhut (talk) 14:16, 4 September 2014 (UTC)

My belated reply: thanks, very nice to see you. For now my contributions will be very scrimp. It seems you have already handled the situation fine, there appears to be no contributions since the 4th september. Cheers, M∧Ŝc2ħεИτlk 23:47, 5 September 2014 (UTC)
Thanks, that one worked, but I asked for protection of Wave packet now. It looks like obstreperous actors are loose... Pardon the "whining"... Cuzkatzimhut (talk) 20:26, 24 October 2014 (UTC)

Generalized coordinates image[edit]

Hi, I just read the Lagrangian mechanics article and got confused by your generalized coordinates image. I think that the caption text of this image (which appears in multiple articles) is actually incorrect. Generalized coordinates are supposed to uniquely define the configuration of the system (as also mentioned on the 2nd sentence of the generalized coordinates article); but in this image, only the arc length parameterization (bottom right) satisfies this properties. For the other choices, there are multiple points on the complicated path that are mapped to the same generalized coordinate value. Am I missing something? Could you fix the image (as it is already used in multiple article)? My suggestions are either to get rid of all examples except the arc length; or if you want to still illustrate other possibilities, use a less complicated path which then would allow the 1d-projection to still be injective. Actually, I just realized that somebody else had already made this comment here for example. Simon Lacoste-Julien (talk) 16:15, 30 November 2014 (UTC)

Hi, yes, I have been meaning to fix those images for a while, as with many numerous others. I'll try and sort something out by today, please hang on for longer. Sorry to keep you and everyone else waiting.
By the way, anyone is free to delete incorrect/misleading images from articles as they please... M∧Ŝc2ħεИτlk 15:17, 3 December 2014 (UTC)

Here are some I made now:

Open curved surface F(x, y, z) = 0
Closed curved surface S(x, y, z) = 0
Two generalized coordinates, two degrees of freedom, on curved surfaces in 3d. Only two numbers (u, v) are needed to specify the points on the curve, one possibility is shown for each case. The full three Cartesian coordinates (x, y, z) are not neccersary because any two determines the third according to the equations of the curves.
Open straight path
Open curved path F(x, y) = 0
Closed curved path C(x, y) = 0
One generalized coordinate, one degree of freedom, on paths in 2d. Only one number is needed to uniquely specify positions on the curve, the examples shown are the arc length s or angle θ. Both of the Cartesian coordinates (x, y) are unneccersary since either x or y is related to the other by the equations of the curves. They can also be parameterized by s or θ.
Open curved path F(x, y) = 0
Closed curved path C(x, y) = 0
The arc length s along the curve is a legitimate generalized coordinate since the position is uniquely determined, but the angle θ is not since there are multiple positions owing to the self-intersections of the curves.


It would be better to draw some simple mechanical examples (pullys, blocks and inclined planes, pendulums and the like) and label generalized coordinates on those, I'll get to those soon for a physical perspective. The ones drawn here should be fine for a more mathematical visualizaton. Best, M∧Ŝc2ħεИτlk 22:09, 3 December 2014 (UTC)

Rather than keep the incorrect image File:Generalized coordinates 1df.svg, I'll replace this with the last two. M∧Ŝc2ħεИτlk 23:38, 6 December 2014 (UTC)

What's up?[edit]

Long time no see.

Exams?

YohanN7 (talk) 13:28, 1 December 2014 (UTC)

Not exams, did those last June. No postgraduate work either, didn't get through the PHD offers (survived the interviews but other students must have had superior transcripts than I have, admittedly it was only a scrape past the 2.1 class)... Only study for me now is self-study with graduate-level books (those savings were worth spending on the dover and other books). Just stuck with a crappy job for now while reaching for worthwhile ones. Nice to see you and others are making productive contributions. Best regards. M∧Ŝc2ħεИτlk 15:17, 3 December 2014 (UTC)

Mail[edit]

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"actually"[edit]

I have made some remarks about "actually" and footnotes here.Chjoaygame (talk) 16:26, 6 December 2014 (UTC)

Thanks for feedback, Chjoaygame. I like the helpful edits you made to the lead to sharpen it up as well. Good job! ^_^ M∧Ŝc2ħεИτlk 23:29, 6 December 2014 (UTC)

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