I want to ask a question. Our teacher taught us that the reference standards are meter, second, and kilogram. If meter and kilogram both depend on time, then time must be the only reference standard. Why include it?
The meta can be used to ask about anything relating to the way the Physics SE works. For example that question you linked is about how best to ask questions on the Math SE.
I'm not sure what you mean by asking for links. Can you give an example of what you want to ask about?
To probably make it clearer, this post provides links to various posts regarding different topics such as How to write math and Enforcement of Quality Standards. Maybe there are links like this for Physics?
I feel that this question should not be closed, as it is a physics-related question that stumps a lot of people, and contributes greatly to myths.
9/11 attack: How can a whole building fall even though impact only on the top of building?
It has been closed as off-topic, despite asking for an "exp...
Hi! I have a question. I want to know what does it mean to say: "the smaller the time interval we have, the greater the uncertainty in energy is" This is to explain the equation delta E * delta t = h where h is Plank's constant. According to my understanding is that the smaller time interval we have, the greater amount of energy we need. Is this correct?
@user777 the energy time uncertainty is more complicated than you think. It does not simply relate an uncertainty in energy to an uncertainty in time like the position-momentum uncertainty principle does.
(Sorry for asking this silly question)
Until yesterday, my username was visible in this circle. But now it does not seem. So I have to search my name under the 'users' section to go to my profile. Am I the only one facing this problem? What is the reason for this?
@ACuriousMind The reason I asked this question is because I'm reading this paper: Ultimate physical limits to computation by Seth Lloyd which said in page 3, the following: " ... the laws of quantum mechanics determine the maximum rate at which a system with spread in energy \Delta E can move from one distinguishable state to another." If this is not what I wrote above, then what he means here
did you read the answer by joshphysics in the question I linked? He explains exactly what $\Delta t$ means
I suspect your source just interprets "on observable has changed by a standard deviation" as "the system has changed from one distinguishable state to another", but "distinguishable state" is not really a formal notion in QM
I am confused whether in this question, the answer by Dale is correct or the answer by benrg is the correct one physics.stackexchange.com/q/590790/113699. Can anyone suggest what’s the correct thing….@Slereah
@Slereah but as benrg points out that if we postulate that speed of light in an inertial frame is c, my understanding of the postulate was too the same that speed of light won’t depend on source direction etc ( only then can it be c always in an inertial frame). Hence the one way speed of light is c ( other wise the 2nd postulate will not hold true; speed of light won’t remain
same in two inertial frames, in one moving towards the right and in one moving towards the left)
but yes you are right, if we use different synchronization conventions, then it does mean that, in the sense of coordinates, the speed of light is faster in one direction
Basically the synchronization conventions is a choice of how you slice your spacetime into spacelike hypersurfaces
@Slereah do you know of any reference that discusses these abstract things in a detail in both in SR or Newtonian Mechanics, like a paper or book or maybe a book on philosophy of space time
Can someone explain to me the difference in the type of radiation from something like a plutonium core vs a particle accelerator?
nuclear fission chain reactions just shoot out a ton of gamma/x-rays? Does an accelerated beam of particles just have a lot of energy thus making it harmful?
So different sources can result of the radiation of different types of particles (note this is a bit different than considering photons as radiation like you do in E&M). As far as I know, for circular accelerators like the LHC, the idea is to get the collision energy high enough to create particles of interest based on the collision alone, so particles below a certain mass range can be created by an accelerator of a given energy. For the linear accelerators I know of, the idea is to accelerate some nucleus and collide it with a target of a given material. You then typically get a variety of…
There's also this nice interactive table of nuclides since the ones on wikipedia don't seem to zoom https://people.physics.anu.edu.au/~ecs103/chart/
Many posters report claims in statements such as
This author claims that…
Some claim that… OR Someone claims that…
I read that…
containing no supporting evidence, source or reference.
Should we insist that claims always be supported in the body of post (question or answer) by a source citation?
(Sorry for asking this silly question)
Until yesterday, my username was visible in this circle. But now it does not seem. So I have to search my name under the 'users' section to go to my profile. Am I the only one facing this problem? What is the reason for this?
Many posters report claims in statements such as
This author claims that…
Some claim that… OR Someone claims that…
I read that…
containing no supporting evidence, source or reference.
Should we insist that claims always be supported in the body of post (question or answer) by a source citation?
