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age 23
visits member for 2 years, 3 months
seen Apr 21 at 15:59

NTS


Feb
4
comment How the torque/moment-of-force can be mathematically defined?
Yes it is, they are not being added, they are being multiplied. Do you have any trouble multiplying distance with the inverse of time to get a speed? This is the same thing.
Feb
4
comment How the torque/moment-of-force can be mathematically defined?
Well... you are not adding position and force which wouldn't make sense. You're multiplying them, which produces a new unit Newton*meter. Mathematically, they both belong to $\mathbb R^3$, so they belong to the same space and that product is perfetly well defined.
Jan
29
comment Why does choosing a time break covariance?
Some simple example would be greatly appreciated, I think that would trigger my understanding. Thank you for your answer by the way.
Jan
29
comment Why does choosing a time break covariance?
That is exactly my question, in which point of defining canonical momentum or legendre transforming the lagrangian do you fix a time? Couldn't you just define the momentum to be $\partial\mathcal L/\partial\dot\phi$, with the dot representing any parametrization of time in minkowsky space?
Jan
24
comment Electric dipolar moment of a half wave antenna
@Georg never mind, the name is irrelevant. It's a wire with that current.
Jan
24
comment Electric dipolar moment of a half wave antenna
@Georg Sorry, half wave
Dec
9
comment Constant quantity associated to symmetry
@bechira I am uncomfortable with stating that as some kind of theorem. I'd expect some kind of relevant content, plus I know how Noether conserved charges come out from symmetries, and I was expecting to see a connection.
Jul
8
comment Light dispersion in water
So if I incide light not normally in a big amount of water, will I see dispersion? Shouldn't then I see dispersion by looking at the sun (when it's NOT on top of the sky) from behind the water, for example in the sea?
Jun
16
comment Decomposition of this wave function in eigenfunctions
Thank you for your help. That's what I initially thought, but he made some reasoning before calculating, and doing that in the case when the highest value for $\ell$ is, let's say, $10$, doesn't seem very efficient.
Jun
16
comment Decomposition of this wave function in eigenfunctions
Thank you very much. I give you the correct answer for completeness.
Jun
13
comment Calculation of magnetic force magnitude from a parmenant magnet
What's vertical pull? What units do they give you for that? Can you link the website?
Jun
12
comment Effect of slits and a lens
Ok, thank you, that: $x=f\sin \theta$ was what I needed, I was using $x$ as a generic variable, meaning angular coordinates: $\mathrm{sinc} ^2(kpd/2)$. Thanks for your help.
Jun
12
comment Effect of slits and a lens
Thank you for your answer, specially the third case. So, the lens still compresses the difraction pattern of the $\sin^2 x/x^2$, doesn't it? i understand they're centered at the same point, but is there a way to calculate quantitatively the position of the fringes in the focal plane of the lens?
Jun
10
comment Dynamic equation
Ok, thank you for your complete answer, you explained it perfectly
May
22
comment Frank Hertz experiment and different jumps
Thank you for the answer and the article. I'm going to read it.
May
5
comment Historic derivation of Wien's law
@LeosOndra Thank you very much for you help and your time
May
5
comment Historic derivation of Wien's law
@LeosOndra I would appreciate it, I don't spek any russian though. I'm not interested in the whole article, only in the derivation of that law.
Apr
26
comment Quantum commutator
ok, thanks you very much
Apr
5
comment Why does the index of refraction change the direction of light
Thank you very much, that analogy ir really good.
Apr
4
comment Why does the index of refraction change the direction of light
Thanks I got it. that picture opened my eyes (even when I have seen that picture like a trillion times)