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seen Apr 17 at 13:29

Dec
2
comment Directionality of angular momentum
It was an implicit assumption, as with any momentum conservation questions.
Dec
2
asked Directionality of angular momentum
Nov
30
accepted Is there a mathematical derivation of potential energy that is *not* rooted in the conservation of energy?
Nov
30
comment Is there a mathematical derivation of potential energy that is *not* rooted in the conservation of energy?
Thank you for the mathematical description. Is there nothing more to energy and work other than 'a value that is conserved' (although not conserved in the same way, or course)?
Nov
30
comment Is there a mathematical derivation of potential energy that is *not* rooted in the conservation of energy?
Where does the equation for work come from? Is that form its definition, or is it empirically based? And is kinetic energy defined by anything, or did physicists mould the equation for it around to fit an everyday thing?
Nov
30
revised Is there a mathematical derivation of potential energy that is *not* rooted in the conservation of energy?
added 66 characters in body
Nov
30
comment Is there a mathematical derivation of potential energy that is *not* rooted in the conservation of energy?
Sorry, I forgot to specify that I was considering about only conservative forces.
Nov
30
comment Is there a mathematical derivation of potential energy that is *not* rooted in the conservation of energy?
As an example of $(2)$, physics.stackexchange.com/questions/535/…
Nov
30
asked Is there a mathematical derivation of potential energy that is *not* rooted in the conservation of energy?
Nov
24
comment In classical mechanics, are complex numbers unphysical?
@tpg2114 Thanks for the answer.
Nov
23
asked In classical mechanics, are complex numbers unphysical?
Nov
23
comment Why do physicists believe that particles are pointlike?
Experimentally at Imperial College London and elsewhere experiments have shown that electrons are pointlike to a great precision. www3.imperial.ac.uk/ccm/research/edm/overview/motivationnon has links to the many results pages, so I thought it would be a better link than any specific page.
Nov
6
comment List of freely available physics books
Feynman lectures are down
Oct
31
comment How do we know the universe is expanding, and not that its contents are shrinking?
When you say 'matter is distributed like that', do you mean that we do not observe precisely enough to see whether or not the FRW metric holds or is it that our observations are accurate enough AND they tell us that the FRW metric is not fully implemented (if that's the right word) in our universe?
Oct
31
accepted How do we know the universe is expanding, and not that its contents are shrinking?
Oct
31
comment How do we know the universe is expanding, and not that its contents are shrinking?
Thanks for the answer, but by Hubble's law the Earth-Sun space (assuming it is a constant) is expanding 0.36 $\mu m/s$. Of course the fact that the Earth-Sun distance varies due to their movements in space, but that's irrelevant.
Oct
30
comment How do we know the universe is expanding, and not that its contents are shrinking?
So is there no self-consistent way that these natural constants could be changing that mimics exactly the fact that if I measure the distance between A and B (which are at rest relative to space (if that makes sense)), later I will measure a longer distance due to Hubble expansion and at the same time these constants remain constant factors of one another?
Oct
30
asked How do we know the universe is expanding, and not that its contents are shrinking?
Oct
29
awarded  Teacher
Oct
29
comment Relativistic mass and imaginary mass
@CrazyBuddy I believe Chernenkov radiation has less to do with the question than you make out- it's more of an electrodynamical oddity than a relativistic one- vacuum Chernenkov radiation would be completely different to non-vacuum.