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12h
revised Does radiation force depend on group velocity or on phase velocity?
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12h
revised Does radiation force depend on group velocity or on phase velocity?
added 61 characters in body
12h
revised Does radiation force depend on group velocity or on phase velocity?
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14h
comment Does radiation force depend on group velocity or on phase velocity?
Sorry, I thought it might have been clear from what I had already written, but I have updated the answer to be even more explicit.
14h
revised Does radiation force depend on group velocity or on phase velocity?
added 839 characters in body
2d
answered Does radiation force depend on group velocity or on phase velocity?
Jul
1
comment Extra dimensions in a black hole
Related: physics.stackexchange.com/questions/5270/…
Jun
30
comment Extra dimensions in a black hole
Perhaps a clearer way to ask this question might be: how are the curled extra dimensions postulated by some theories of quantum gravity expected to behave near a black hole singularity?
Jun
29
comment Does radiation force depend on group velocity or on phase velocity?
This is a great question. Here's a link to another discussion of a similar question -- I'm not sure how authoritative it is, though. quora.com/…
May
25
reviewed Reject Is it possible to express continuous growth without using transcendental numbers?
May
20
comment Angular momentum - proof for integer eigenvalues
I'm confused, how did you prove that j is a half-integer number? I thought it could either be an integer or a half integer (see my response here: physics.stackexchange.com/q/27899) . Once you've proven that for j, then I agree with you that the conclusion for m follows automatically from the 2nd statement in your question
Feb
20
comment A conical pendulum. A textbook claims one can start the circular motion in an unintuitive way
What I had in mind was the centrifugal force, the notorious "fictitious" force that appears in equations of motion when written down in a rotating frame. My thought was that if the centrifugal force were greater than the gravitational restoring force, then the slightly perturbed rotating pendulum would continue to move out. It's possible I'm overlooking something simple, though, especially considering that your experiment isn't confirming this idea. Maybe try again with a shorter string, and slightly larger initial perturbation?
Feb
20
comment A conical pendulum. A textbook claims one can start the circular motion in an unintuitive way
Neat! Your calculation seems correct to me. I would have thought the drill would be spinning faster than that, so I am a bit surprised. I'll have to ponder this some more. Also, ideally, your experiment should use an angular velocity that is not too much different from the pendulum frequency, so that the equilibrium angle is not so large that you enter the nonlinear regime.
Feb
20
answered A conical pendulum. A textbook claims one can start the circular motion in an unintuitive way
Jan
28
awarded  Yearling
Nov
7
reviewed Approve Trajectory of a bomb dropped from an aeroplane
Nov
4
reviewed Edit Why does Einstein's equation of relativity exclude space and time?
Nov
4
revised Why does Einstein's equation of relativity exclude space and time?
rewrote the given equation using MathJax
Oct
10
comment Why do Oreo crumbs float to a single glob at the very center in a glass of milk?
If this were happening at the bottom of the cup, it would be explained in the same way as the so-called "tea leaf paradox" (en.wikipedia.org/wiki/Tea_leaf_paradox). But the fact that it's happening at the surface means something else is going on.
Sep
30
awarded  Explainer