darklight03/StackMIAsub huggingface dataset:
I've read other answers about how vinyl records reproduce sound, but they don't quite address a main thing I'm curious about. Play Middle C on a piano or a Clarinet, its the same note that can be played at the same volume because the main note is the same. You can tell the instruments apart because there is a different timbre in the instruments due to the components of the other harmonics present in the sound that differ between the instruments. You can break this down using Fourier Analysis. Part of the reason for these differences is the natural frequency of the materials involved. Strike metal with a small hammer, you typically get a higher pitched sound than if you strike a similar volume of wood. A vinyl record has its own natural frequency, yet it can sound just like instruments neither of which sound like each other. Somehow the natural frequency of the vinyl doesn't matter. What's going on there?
If an isolated conductor has a net zero charge and is not in an external field, would the free charges still move to the surface of the conductor eg. a conducting sphere? Wouldn't this create an electric field inside the conductor pointing radially outwards as there would be positive ions within the conductor and negative charges on the surface? And then wouldn't the electrons move back to join the positive ions? [I understand how free charges will move in a conductor to cancel any external field, cancelling the external field inside the conductor, but then wouldn't there still be a field pointing radially outwards?] I also don't understand this in terms of energy - why is it a lower electric potential energy position for the charges to go to the surface - wouldn't it be lower energy for the electrons to go back to the positive ions? Gauss's law talks about there being no charges inside a conductor, but wouldn't there still be all the positive ions left there if the conduction electrons have gone to the surface? My guess is that people are usually talking about any NET charge going to the surface of a conductor. But wouldn't an isolated conductor at equilibrium (as in the general textbook questions on this) be net neutral and so then not have charge on the surface?
I understand my question sounds stupid but hear me out. I wondered if protons or any charged particle could generate photons and I found this wonderful answer that says yes: Does shaking an atom produce photons? The issue now is that the more I thought about it the more I became confused and here is why. If any shaking charged thing can make a photon, well, which way does the photon choose to go into? I don't have a clear understanding of photons so maybe that's the problem, so to better answer me I'll give my understanding. Photons are packets of energy that represent an oscillating electric and magnetic fields. Please correct me on that if i'm wrong, I'm mostly using the visual model of a photon when i describe it. How does a photon decide in which direction it moves in? Is it just completely random?
I've gotten some contradictory answers on where the definition of the element within a set comes from. From a quick Google search, I got this strange idea that the definition of the element comes from the definition of a set. I reached this conclusion because some websites state simply that the element is A member of a set But I feel this results in some type of circular logic (At least I think that's what this logical fallacy is called). Since the definition of a set is A set is a collection of objects whose contents can be clearly determined. The objects in a set are called the elements of the set. (Robert blitzer college algebra) I am almost certain that the issue here lies in the definition of an element I found, But I can't seem to find a definition of the element that is independent of the set so to speak. I hope you guys can help clear this up for me thanks
Suppose the situation where an object undergoes linear motion at a constant velocity on a frictionless surface. This motion is often introduced as inertial motion, which is the motion described with Newton's first law. On the other hand, suppose the situation where a person applies a force to an object on a surface with friction, adjusting the force to balance the kinetic frictional force and causing the object to undergo linear motion at a constant velocity (here assuming no torque). In terms of the fact that net force exerted to the object is zero, I know there has been recognition that the motion of the latter case can be interpreted as inertial motion according to Newton's first law. However, is such motion really an example of inertial motion? Such motion seems to be rather different from the motion of the former case (close to Galileo's original thought experiment in which the essence of inertial motion is highlighted in idealized situation with no friction). Or is it just a problem of how we define inertial motion?
I have an understanding of electrical circuits, however I am very interested to know more about electromagnetic waves radiation. In particular I want to know how an oscillating voltage causes the electrons move inside a conductive antenna. Voltage is only a difference in electrical potential in our local circuit, it is only difference between electrical potential of two nets (ex ANT and GND) so how the ANT net can itself cause movements of electrons inside an antenna? (because in some circuits the antenna is only connected to ANT.) I want to know which physics model explains this phenomenon? as far as I know circuit theory doesn't explain this behavior. so It should be something else. I know there are some formulas to model electromagnetic radiation, however I want to build an intuition around this, I don't need formulas to solve problems. Also I know that speed of the light has relation to design of the antenna, so I think the theory should include speed of the light as well. I prefer to not get very deep in physic subjects, so I am looking for the most higher level theory/model which is able to fully explain this :)
This is a discussion I was having with a friend: Its very likely that the temperature of the water you place a tea bag in while change the flavor of the tea (although I don't know why exactly from a physics perspective) But suppose I have water at a certain temperature: If I let the teabag naturally sit and soak in the hot water.... compared to taking a spoon and pressing/squeezing the teabag as soon as it lands in the hot water: will the flavor of the tea be different? From a diffusion perspective, I know that squeezing the tea bag in the hot water changes the color of the water much faster compared to letting the tea bag rest. But based from a physics perspective, looking at the interaction of the water and the tea molecules - will accelerating the diffusion process of the tea by pressing/squeezing change anything about the tea? (e.g. intensity, flavor). Are there any physics related equations (e.g. statistical mechanics, thermodynamics) that can explain this (if this hypothesis is true)? Thanks!
I downloaded a latex template for Wiley journal articles, and can open the template file but cannot seem to get Texstudio/Miktex to find the .cls file. The template comes with a latex file which uses the class as an example, and if I open that right in the extracted ZIP folder, all is well; however, if I save-as anywhere else, I get a "cannot locate name.cls file". I have made sure that I saved the extracted ZIP folder within a directory listed in the MikTex path (have tried two different locations) and I have refreshed the filename database (multiple times) but still the same error occurs. This also happens if I open a blank file and attempt to use the class. I have closed and opened TexStudio a number of times, but I am unsure of what else I can try.
During the last few days I have been interested in the gravitational hierarchy problem and the different explanations for it/solutions to it. Among the most "concrete" (insofar as anything this complex can be concrete) explanations are several realisations of the so-called "brane cosmology". In these, whether they be the original ADD model or some string theory model, the standard model particles/modes are confined to a brane (either due to them being open strings or some other effect) while gravity/gravitons can freely propagate into the so-called "bulk", therefore allowing gravity to "leak" away from "our" spacetime thereby explaining why it's so weak. Common to these theories is that while these dimensions can be taken to be either compact or non-compact (but often are assumed to be compact) they are "large" extra dimensions. Now in your "garden-variety/lift pitch"-string theory the necessary extra dimensions are assumed to be very, very small and compact. My questions now revolve around the parallels of these Kaluza-Klein compactified theories and the brane cosmology ones in regard to the hierarchy problem: Can standard model particles/modes access the extra dimensions? I seem to recall that this should only be possible at "high enough" energies but I am unsure. Can gravity/the graviton access the extra dimensions even at low energies? If so, why? What is the mechanism/explanation for this? If neither of the above yields a similar solution to the hierarchy problem as in the brane cosmology scenario, how is the hierarchy problem solved in these "classical ", small-extra-dimensions Kaluza-Klein types of theories?
So imagine the classic science experiment where you take an empty aluminium can and a rubber bar that you charge with fur. At first, that can is electrically neutral. Two different cases now that I want to discuss: If I put the can on a desk made out of wood, the can will be attracted by my charged rubber bar due to influence. So the electrons in my rubber bar push away the electrons being in the can as far away as possible (the other side) and so the rubber bar only "sees" the protons. If I put the can on a desk made out of a metal which is grounded, what happens then? Still influence? Or is the electrically neutral can now positive due to electrons escaping to ground? Would love to hear some thoughts. Best regards
Can we determine the truth value of the statement "if A then B" knowing only that B is definitely false whenever A is true, for example, "If you live in Paris, then you live in London." From what I understand about truth tables, this on the face of it is indetermined because it could be true or false based on whether you live in Paris and not in London, or you don't live in Paris. But at the same time, the fact that we know that whenever A is true B has to be false, seems to go against the purpose of implication, that whenever A is True B has to be True, and from that alone, the conditional statement can't be anything other than false? The book I'm reading says that the statement in the above example is false.
The existing English language term needs to refer to a robot that can navigate environments and it incorporates a human who is present virtually inside the robot from a remote location. The human navigates the robot and communicates with the environment in real-time. The closest example are the so-called telepresence robots being tested for use in classrooms or offices, but they are not exactly what I am describing. I feel like there is a term for such a machine vessel that 'embodies' a human, or that there should be such a term. The terms robot or cyborg do not describe this vessel. I can imagine in the near future a humanoid robot that is not driven by AI but by a human from a remote location using VR with ability to sense the environment (e.g. sense of touch). For example, this would benefit persons with significant mobility disabilities by allowing them to be present and interact with environments, the idea behind the current telepresence robots but in a much more integrated way between the remote human and the machine, and more interactive with the environment. So, to recap, is there a word for such a machine vessel virtually occupied by a human?
In the picture below, mountains farther away blends into the color of sky, this is "atmospheric perspective", caused by atmospheric scattering. This effect is also called "fog". But dark blue appears in the middle of the [green -> light blue] gradient somehow. Why? Is there a physically-based model to explain that? In many video games, they used linear gradient to simulate the fog. The color what we see is a linear interpolation between the color of the object and the color of sky. It looks like the gradient in the right side of the picture. But that isn't realistic because of the missing "dark blue" color, so mountains in video games usually looks too grey. My guess: The dark blue color is caused by Rayleigh scattering. The white color at the farthest mountain is caused by Mie scattering. Somehow combine them makes the fog both blue and white. But I have no idea how.
In a room at normal room temperature, certain materials, such as metal, glass, ceramic, or rock, will feel cold to the touch, but others, such as wood or plastic, do not so much. Which physical properties do the former materials have in common that cause them to be cold to the touch but the others lack? The fact that wood is porous? Solid plastic pieces still do not get/feel as cold even though they are not porous. Most sources point to thermal conductivity, but how can that alone be the answer? Rock and rock-like materials (such as glass and ceramic) have a very poor thermal conductivity whereas metal has a very high thermal conductivity. I know that because rocks take a long time to heat up and cool down in a fire, but metal takes not very much time. Which physical properties (might be more than one) determine whether a material at ambient temperature will be perceived as cold or not?
As a forward, I'm no a physicist or a student of it. In fact I'm pretty ordinary. So if I mischarecterize some concepts, bear with me. So I was reading up on some of the new technologies and then I had a moment. I am wondering if you could use quantum entanglement to transmit data across a vast distance, theoretically even light years, in an instant. I was debating this in a youtube clip where there was a whistle blower from the antarctic and they were speaking on this. My "opponent"(I guess?) Stated that measuring any entangled particle removes the connection, but quantum computers can use gates that flip an electron spin without disrupting the connection. Another objection was multi light year transmission, but I thought that should be fine since according to the theory, it's instant, no matter the setting. So basically I'm wondering with the current tech that we have, technically couldn't we set up an experiment to send a byte of data via quantum entanglement by changing the state of an electron, using a gate to measure it on the other end, and translating that to a binary digit? In other words, do we have Faster-Than-Light communication on the horizon?
My understanding: electrocaloric effect relies on polarized molecules lining up to an external electric field, which lowers the local entropy and thus heat is given off to the surroundings. When the field is removed, the molecular dipoles again arrange randomly, which increases the local entropy, thus heat is taken in from the surroundings. I ask about a macro level system. Here I have micron sized particles, each particle made of two hemispheres using different materials from the triboelectric series. These serve as my "molecules". Upon initial shaking, the surfaces rub and so each particle has a dipole. Before shaking: After shaking: Now I turn on an electric field and vibrate the container a little so the particles loosen and align themselves to the field. This vibrating is kind of like of how they used to hammer the living hell out of heated iron in a strong magnetic field, so the magnetic domains align as the object solidified. Now I can't think of any reason why this won't display the electrocaloric effect. And since here we don't rely on the molecule shapes, crystallization, polarization and the intermolecular forces that prevent the dipoles from completely aligning themselves, I think this could display interesting levels of cooling and heating. Of course, I'm a nobody, so to you experts I hand over my question. Will this work, and if yes, can we quantify the effect using any equations?
I'm looking for a word that effectively conveys an attitude showing a preference for having a child related to oneself ... ie, a lineally/genetically-related child. In particular, a word that would fit the following example: Michael had a _____ attitude, he wanted children of his own and / or possibly a noun form: Michael was a _____ unlike Sam who was a non-_____ which would be helpful in distinguishing between people that prefer to have their own children and those that are happy to adopt, foster, etc. I had considered "autogenic" ... "auto" meaning self, and "genic" meaning "produced by" ... and even "progenic" (or "progenetic" possibly) which might work here, "pro-", I take to mean "following" or "in favour of" which in combination with "genic" / "genetic" relates to genetic lineage or heritage. However, I'm not sure I've constructed them appropriately, or whether they're right or not.
Scientocracy (to my understanding and as my intended meaning) is government by results, i.e., eschew policy debates to instead argue and then agree on metrics, run an experiment and then transition to whichever solution produces the best outcome as determined by the agreed upon metrics (of course, if cultural, climatic or other considerations make a new policy ineffective in a certain place, the policy should be revoked or adapted there). My question is what is the 'ism' associated with this? Scientocracism isn't a word, and ends with racism, so that doesn't really work. Technocracy (a related, if more loaded term) has the same problem. An example sentence would be: I believe in representative democracy, but I also believe in [] because while I think that we should be able to elect people to represent our interests - and fire them when they fail - I also believe in results.
In the preface to Landau and Lifshitz's Statistical Physics, they comment the following In the discussion of the foundations of classical statistical physics, we consider from the start the statistical distribution for small parts (subsystems) of systems, not for entire closed systems. This is in accordance with the fundamental problems and aims of physical statistics, and allows a complete avoidance of the problem of the ergodic and similar hypotheses, which in fact is not important as regards these aims. After explaining that they will consider (macroscopical) subsystems of the whole closed system, they claim A fundamental feature of this approach is the fact that, because of the extreme complexity of the external interactions with the other parts of the system, during a sufficiently long time the subsystem considered will be many times in every possible state. But this is very similar to the ergodic hypothesis, is it not? From my Stat Physics lecture notes, Given a sufficiently large time, any closed system will approach arbitrarily closely any point in phase space I don't understand how considering subsystems overcomes the need for this hypothesis, neither what advantage it has. It seems to me that the authors are using the complexity of the interactions between the subsystem and the rest of the system to grant credibility to the claim that the subsystem will eventually have populated the entire phase space. But why isn't this equally credible to stating the ergodic hypothesis?
Im not necessarily talking about emf (and also not considering rotation) , but rather the potential difference created due the induced electric field to balance the lorentz force on the electron. For example if the disk is moving toward the right and the magnetic field is into the screen then the lorentz force is acting on an electron downwards pushing it down. now due to the excess of electrons downwards an electric field is created top to bottom which increases until the lorentz force is equal to the force due to the electric field on the electron, resulting in an electrostatic condition. So my question is does this actually happen? if not why dosent it happen? Im a bit bothered by this because according to faradays law there should be no emf induced in the disk but according my reasoning there should be a potential difference. Is there a difference between emf and potential difference?
As I understand it, the (real) index of refraction is given by the ratio of speed of a monochromatic light wave in vacuo versus speed in medium. When it comes to the question of propagation of a light pulse in a (dispersive) medium I know that I need to calculate the group refractive index to obtain the propagation speed of the pulse. My question specifically now is, if it is possible to use radiative transfer theory to calculate light pulse propagation in a scattering environment embedded within a medium (not vacuum)? If the former is possible, can that speed be said to be the effective group velocity of the mixture of the scatterers and medium? Further can this effective group velocity be used to calculate an effective group refraction index? Background: Although I have no working experience with radiative transfer theory I can imagine that it would be possible to use it for calculation of attenuation related values such as the imaginary part of the index of refraction, but I cannot see how it would be possible to get at the real part of the index of refraction.
I've recently watched this video about an electromagnetic ring accelerator. I get how it works: it uses controlled electro-magnetic coils to accelerate metal balls' Passing trough one of the coils has two stages: when the coil passes enters the coil, the coil is powered on, generating an electro-magnetic field, accelerating the ball towards the center as the particle passes trough the origin of the coil, the coil is quickly powered off and the ball continues forward What I am curious about is exactly what forces act on it. Searching online there appear to be some inconsistent answers, but it always either is the magnetic force or the Lorenz force law. From what I understood the magnetic force is purely for describing magnetic attraction, either between two magnets or a magnetic (ferromagnetic?) object and a magnet, while the Lorenz force law is the combination of the magnetic and electric laws. Could somebody explain which of these two is and what exactly their formulas are in the context of the balls passing trough the coils?
For example, ZFC and ZF. I have come across the notion of pure and applied mathematics, and how the development of the former can (and is usually intended to) lead to the furtherance of the latter. In this case, how do we know that the axioms we do pure maths with are "sound"? For me, there is no point in doing something as rigorous as maths unless we are certain it could at least possibly provide a practical use to us, however subtle that use may be: otherwise, it is just an elaborate (and hugely unproductive) mind game. I suppose my question boils down to why we do maths and what it is. If its a way of abstractly describing physical natures and phenomena (like Plato thought), I'd have thought you could test axioms with the scientific method, in which case there would be no confusion surrounding, for example, the millennium problems. There is so much nuance about axioms and proofs, truth, falsity and their natures that really interests me, and I would like to know more about, but I don't know where to start. I have heard of "metamathematics" as related a field of study, which is why it's included in the title, but I honestly don't know much about it. I also appreciate that ZFC and ZF may be bad examples, in which case please point out why. Thank you!