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seen Apr 17 at 13:29

Apr
6
comment Why is $\phi$ constant in the hyperbolic Lorentz transforms?
I make that point in my question and it doesn't follow from that that $\phi$ doesn't depend on the two spacetime co-ordinates being studied.
Apr
6
comment Why is $\phi$ constant in the hyperbolic Lorentz transforms?
Thank you. Can the analogy between Euclidean and Minkowski space (specifically, the transformations) be made more rigorous? For instance, this question I asked on MSE seemed to indicate that there's not much geometric analogy to be made between hyperobolic and usual trigonometric functions, which makes me dubious of such analogies.
Apr
6
comment Why is $\phi$ constant in the hyperbolic Lorentz transforms?
Part of my problem may arise from assuming that the only reason for $(1),(2)$ is $(*)$: I don't know whether that assumption is correct.
Mar
25
comment Relative angular velocity and acceleration
@ja72 Yes, here, although I'm less sure that my interpretation of $\alpha$ as a cross product is correct.
Oct
5
comment What IS reflection?
Why is it that in specular reflection, all wavelengths are reflected, whereas in diffuse reflection, absorption of some wavelengths occurs before emission, so that only some wavelengths are reflective? I assume it's because the final sentence of your last comment does not occur readily in rough surfaces (why?).
Oct
3
comment Whose reference frame to use for $d \theta$ near a black hole?
@BenCrowell by the way, am I actually able to use the SM if the satellites are orbiting (I ask as it's not accurate if the black hole itself is rotating)?
Sep
30
comment Whose reference frame to use for $d \theta$ near a black hole?
Do you have a link detailing this thoroughly (ideally without tensors or similar wizardry)? I've got most of my information from Wheeler's introductory 'Black Holes', and whilst it's brilliant in getting intuition, it's often not very rigorous.
Sep
30
comment Whose reference frame to use for $d \theta$ near a black hole?
I meant it to be transverse. Thank you, this was one of the problems I was having earlier. I'm trying to deduce the difference in the time signals between being sent by GPS satellites and Earthlings receiving them.
Sep
30
comment Whose reference frame to use for $d \theta$ near a black hole?
I was careless with pasting the second equation. I realise that $c=1$ is useful, but haven't been doing GR long enough to really feel at ease with it.
Sep
28
comment Pendulum Hits a Mass and Spring
It's not entirely clear what the situation is. Could you explain in more detail where the mass, spring and pendulum begin, or provide a picture?
Aug
16
comment What is the maximal height for a water rocket's flight?
Thanks, but the part of the question I find especially is determining $\mathbf{u}(t)$ and $\mathbf{v}(t)$.
Aug
16
comment What is the maximal height for a water rocket's flight?
@Johannes Here I meant it to mean 'initial'. I'll edit for clarity.
Aug
16
comment What is the maximal height for a water rocket's flight?
@Johannes Yes, as the water cannot move further up than the top of the cylinder.
Aug
16
comment What is the maximal height for a water rocket's flight?
@RedGrittyBrick No (is the wording particularly wooden?). I'll add them.
Jul
15
comment A rope attaches the Moon to the Earth. What happens?
@WetSavannaAnimalakaRodVance It is true; the edit was due to the (surprising) failure to realise the irrelevancy of a real string breaking. However, surely if option 1 were to occur, the distance between their COM would decrease with time?
Jul
6
comment A rope attaches the Moon to the Earth. What happens?
@dmckee You're right. I really meant 'ignore any effects of the moon's axial rotation' (i.e. assume the string is attached to the moon's centre and can move through the Moon without resistance).
Jul
5
comment A rope attaches the Moon to the Earth. What happens?
Would the close-voter care to explain how I could improve this question? I must commend how quickly you have read through the question.
Mar
12
comment How is Gauss' Law (integral form) arrived at from Coulomb's Law, and how is the differential form arrived at from that?
Thank you, Qmechanic.
Mar
12
comment How is Gauss' Law (integral form) arrived at from Coulomb's Law, and how is the differential form arrived at from that?
I intuit equation (2), but why cube $\delta(\mathbf{r}-\mathbf{r_i})$?
Mar
12
comment Proof that flux through a surface is independent of the inner objects' arrangement
@joshphysics Thank you; yes I do. It's finally clicked where that derivation fits in to the derivation of Gauss' Law. Thank you all for the patience!