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12h
comment How does conservation work in wormholes?
"spacetime curvature involved in a wormhole is qualitatively no different to the spacetime curvature around, for example, the Sun" So there is actually no way to distinguish where is the inside and where is the "normal" spacetime? And I could exchange energies and momenta with that matter at any time during the travel while only conserving the totals, right?
1d
comment Mass or no mass?
I believe this is the canonical article: arxiv.org/ftp/cond-mat/papers/0509/0509330.pdf It seems unlikely that this speed will be irrelevant of frame...
1d
comment Mass or no mass?
"Some systems have $m=0$, and these systems always have momentum relative to your inertial frame. Indeed, you will always observe their relative velocity to be precisely $c$." Is it true about the massless electrons of graphene?
Aug
27
comment Are orbiting planets an example of perpetual motion?
@LuboŇ°Motl, but the planets are accelerated all the time, aren't they?
Jun
4
comment Total current of two sources in series?
@dmckee, as far as Kirchhoff's theory goes, I agree to Will's answer. But maybe you can demonstrate application you had in mind?
Jun
4
comment Total current of two sources in series?
Yes, that's about as much as I can get out from those equations myself.
Jun
4
comment Total current of two sources in series?
@Will that is all the information he supplied.
May
22
comment What is the effect of humidity in temperature?
@user61001, yes, apparent one. If humidity is higher, it seems hotter to people compared to medium or low humidity.
May
19
comment What is the effect of humidity in temperature?
"Tashkent" is synonymous for "very hot". What's with the outside? I don't really understand the new question.
May
19
comment can be exist the negative mass?
Physics become interesting when you consider exotic and scifi-like things. Even Newton's second law becomes funny if you consider negative masses :)
May
19
comment can be exist the negative mass?
And negative masses would attract each other, but repel positive masses, right? That's why they are somewhere far :)
May
19
comment Problem with a rotating frame of reference on the South pole
@Althalos, there is no centrifugal acceleration on the axis. In which direction could it be there? Your formula is correct, but the $R$ is distance from axis of rotation which is $0$ in your case.
May
18
comment Physics of every-day life: rotating bag of tea
I think it's just the torque that's stored in the thread...
May
18
comment Problem with a rotating frame of reference on the South pole
Rotating frame in which train is going straight (as says in the exercise). Yes, $\Omega$ is. Try $\tan(\theta)=F_c/F_a = a/g$. Also $\tan(\theta) = \sin(\theta) = \theta$ (in radians) should for work such a small angle.
Apr
28
comment Why does the fundamental mode of a recorder disappear when you blow harder?
@Georg, a few years late answer, bet I wanted to add that the higher mode does not slowly overtake. It's a sudden shift of pitch.
Apr
28
comment What is the exact mechanism by which time dilates?
Great answer except "Lengths just look different in different frames. Similarly times look different in different frames." I think it is important to understand that length don't look or appear different in other frames. They are different in other frames.
Apr
28
comment Confused about the Photoelectric Effect?
Yes, w/h is correct.
Jan
19
comment Does quantum mechanics allow faster than light (FTL) travel?
Umm, superluminal signalling. I am not asking for true violation of SRT, just something similar to tunneling but without a barrier. There's no need to violate any theory as long as speed exceeds $c$ :D
Jan
16
comment Does quantum mechanics allow faster than light (FTL) travel?
Sorry, I realized that by QM people understand certain theories, but my aim was to actually ask about actual (experimental?) quantum physics.
Jan
16
comment Does quantum mechanics allow faster than light (FTL) travel?
Please see the reformulated questions, I want to know about actual physical (experimental) QM, not what classical QM theories state or not.