Nature Definition and 730 Threads

If we have two points P and Q in undeformed material and after deformation they become P' and Q'. The deformation tensor is the derivative of the displacement. What is the displacement? vector PP'? or the change from PQ to P'Q'? is the second question is the strain "change in length". Why the...

In looking at the definition of a Hausdorff dimension of a space S = inf{d>0: inf{Σirid: there is a cover of S by balls with non-zero radii} =0} where i ranges over a countable set, it would appear that it would be acceptable to take the index set to be finite, but I am not sure how you would...

Homework Statement Please help me answer thew question in the image.[/B] Homework Equations Current Density J=conductivity X Electric field[/B] The Attempt at a Solution As the current density depends on the conductivity of the material through which the electrons constitutuing it are...

Earlier this morning I came across this article -- https://phys.org/news/2018-09-errors-quantum-world.html -- which is about an open for all article in Nature Communications -- https://www.nature.com/articles/s41467-018-05739-8 I've yet to fully work through the paper, but if this thread is...

Can charges collapse under coulomb attraction like charge-less matter does under gravity? In a way it's similar to asking about the lower limit of coulomb force if there is any. Also, does Pauli exclusion principle save the day just as in the case of gravity?

Hi, Sorry, I had to pick a prefix but please feel free to reply as you see fit. I just joined to seek opinions on various things and hopefully learn some other things as well. I am a retired GIS analyst programmer. Completed 1st level multistrand science and maths in high school 1976 but...

Is symmetry a general aspect of physical nature?

The asks for us to find the nature of roots of the following equation ,i.e,rational or irrational nature of the roots: the Equation is : http://www5a.wolframalpha.com/Calculate/MSP/MSP7106108efdacf0gb84ie000039f29d33b6hie7ic?MSPStoreType=image/gif&s=56&w=63.&h=18.x^5+x=5 I have been able to...

First question: Within experimental error all measurements of neutrino and light speed in vacuum are consistent with c, but one way speed measurement of light is well proscribed, so is a one way speed measurement of neutrinos also proscribed? I have more questions, but maybe just clarify this...

im curious as this question came up in a chemistry forum and it's more of a physics question I believe . State changes between elements of near similar number , what constitutes the extreme phase changes ? It was answered that there is no real answer for why the phase differences occurs at...

In Multiverses where there are different constants of nature such as the mass of the electron or the value of the strong coupling constants. Where are the values stored? If there were no compactified calabi-yau manifolds that produced the values and they were just like that. What maintains the...

If friction is electromagnetically attractive force and the normal reaction is electromagnetically repulsive force which it obviously is. But how is it possible to have different type of force as the component of a single force i. e. Contact force over the nature of which I have got confused!

Or in other words: The renormalization group is a systematic theoretical framework and a set of elegant (and often effective) mathematical techniques to build effective field theories, valid at large scales, by smoothing out irrelevant fluctuations at smaller scales. But does the...

It´s not a technical question, is about why the classic mechanics and even quantum mechanics equations are first or second order? ¿Exist any model with up order derivates?

Interesting Article in Nature and looks like better news (as opposed to doom and gloom) things may not be as bad as previously predicted. It will be interesting to follow further research as we gain more data and produce more accurate climate predictions. Unfortunately, the article itself is...

The science that’s never been cited. Nature investigates how many papers really end up without a single citation. https://www.nature.com/articles/d41586-017-08404-0 Publishing by--and for?--the numbers http://science.sciencemag.org/content/250/4986/1331

Mod note: Moved from Precalc Homework, as this seems to be a more general question. Hi, Which mathematical objects (numbers, functions, figures, etc) are more common in nature? I mean the mathematical objects which could more easily be identified with nature. For example, circles and triangles...

If supposed you could locally change any constant of nature in a test area in the lab say the the size of aquarium and you put a marble inside.. could you make the marble bigger and smaller, heavier or lighter by adjusting any of the parameters? or even make the marble explode? What would happen...

Hi, How do you differentiate between fields from a new theory or new fundamental forces? For example. If QM is replaced with a new theory, would the extra dynamics and degrees of freedoms be new forces of nature or can they be non-force or field related, can you give some examples to...

Protons are +1 charged, electrons -1, so that's makes two charges, but how does antimatter charge relate to normal matter charge?

You may know I started a thread on this forum asking questions about the statement in General Relativity that "the laws of nature are the same in inertial frames". Guessing about the answers I got, I arrived in the following conclusion. I'd like to know whether these make sense & are correct or...

Hello all, I am having hard time to know if the finite angular displacement really a scalar quantity? In some books they say angular displacement when finite is Scalar and when infinitesimal small is Vector, with direction perpendicular to plane of circle government by right hand rule. I...

QT would be easier for me to cope with if the interference and diffraction observed experimentally with microscopic objects could be explained entirely by the commutation relations of observables and not by invoking wave properties. This comes down to the question - if we measure two...

Hello everyone! I hope I write in right forum branch. The reason is that I have a question in my mind for a while. Maybe you can help to understand it. So, I am game developer, and one time I was using 2d physics engine to simulate motion in game. And I found out that in that engine, for...

Just what is Information. That is in Physics how is it conceived? Is it a particle a wave a field or is it another thing in nature entirely. When info is exchanged what is being exchanged Or is it just a maths concept that has no physical reality. Et cetera et cetera. I have looked at other...

I'm well aware of the common adage and quantum fact that, until a particle is measured by some sort of instrument, it exists in a state of superposition, can interfere with itself, etc. My questions pertains to the definition of "measurement". In order for something to qualify as a measurement...

Hi, Some time ago I was looking for lightning ball videos on youtube. I observed some strange phenomenon recorded on one of the videos. Before a lightning ball is created, some "dark" ball is coming from above and then it immediately changes to the lightning ball which is moving at different...

First, if you want to refer to the Schrodinger Equation only.. is it only called Quantum Mechanics? Or does the word Quantum Mechanics also include Quantum Field Theory? If true. Then what words should you refer to the non-relativistic Schrodinger Equations only? About the forces of nature. The...

I am a bit confused about my conceptual understanding of "light". As always I warn that I have only the simplest naive understanding of physics. In thinking about vision, especially color vision, I understand that color as such is not a real property of the external world. Nor for that matter...

Im quite fascinated over how Earth is constantly trying to stabilise itself. What is your most interesting observation or 'happening' about climate change?

So I've been trying to wrap my head around this one for several hours now and it just has me stumped. I'm begging, someone, anyone, walk me through it before I swear off numbers for life hahah (Part b) Imgur: The most awesome images on the Internet Thanks in advance for any help anyone can...

Within the context of the de Broglie-Bohm pilot-wave theory, can anyone explain what the pilot wave is in physical terms? I’m having a hard time understanding how, for example, the pilot wave influences the trajectory of a photon in the double-slit experiment. Are we dealing with...

Homework Statement Homework Equations equivalent tension coefficient tDE= applied force/distance between points D and E = 17/SQRT(1[^2+2^2+4^2) = 3.7097 The component of the 17kN in the x-direction = Δx X tDE = -1...

https://www.sciencedaily.com/releases/2016/12/161219085020.htm http://www.skyandtelescope.com/astronomy-news/no-dark-matter-from-lux-experiment/ I believe that WIMP theory has been the leading contender for dark matter in the past, but the null results from LUX, PandaX, Fermi and LHC would all...

I am curious why a more intimate relationship between light and empty space is not something one ever hears about when I think about the three obvious examples of why there seems to be a relationship. 1) Light follows a curve when in a curved spacetime (a gravitational field), 2) photons at...

We define a cyclic group to be one all of whose elements can be written as "powers" of a single element, so G is cyclic if ##G= \{a^n ~|~ n \in \mathbb{Z} \}## for some ##a \in G##. Is it true that in this case, ##G = \{ a^0, a^1, a^2, ... , a^{n-1} \}##? If so, why? And why do we write a cyclic...

This question is about the use of bar on a fermionic field in a Lagrangian, the use of arrows on external fermion lines and the particle-antiparticle nature of a fermion. For illustration of my question, I will use the following the charged-current interaction of the Standard model...

This paper; https://arxiv.org/abs/1702.03050, Experimental demonstration of a fifth force due to chameleon field via cold atoms, by Zhang claims detection of yet another 5th force of nature. I recall a similar claim from last year by Jonathan Feng, et. al.; https://arxiv.org/abs/1608.03591...

Hello, I'm not very familiar with this problematics. So sorry for (maybe) incomprehensible terminology. I study physics and math and now I heard about chaotic behavior of many very fundamental equations describing a nature, when they evolve (when we want to know what will happen in future). I...

This post is a result of reading RKaster's links and I am wondering if there is some evidence that supports measurement being a two stage process. In the Stern Gerlach experiment the particles are in superposition until measured. But is the superposition ended once they enter the magnetic field...

Homework Statement If an object had been projected horizontally with the same magnitude as in the depicted situation, how would the motion compare with that of the object in the diagram? (I have drawn the diagram in my attachment and have done questions c and d but I don't understand question...

Hi I am writing my final Mathematics exams for Grade 12 in South Africa in 5 days. I am well prepared with an aim of getting 100%, but one concept in functions might prevent that - the concept of how the nature of roots are affected by vertical/horizontal shifts in a function, and how to...

Why reducing property of dioxide decreases From SO2 to TeO2

In the Bell type experiment is the hidden variable just a function of the state or a function of the state and the detector?

What is the nature of the randomity that results in where a photon is absorbed? I'm thinking of the double slit experiment with single photon emmisions. There is the greatest probability of absorption in the middle reagon, but despite that the photon sometimes goes to one of the far sides. What...

I have been reading some books (Allendoerfer, principles of math, Zakon, series of mathematical analysis, R. Courant, what is mathematics). I have learned that some of the basic fundamental, the msot bare bones of mathermatical concepts and definitions have to remain undefined. These are set...

As I understand it, in string theory the constants of nature can taken on a huge different number of possible values and when the universe cools after the big bang these constants of nature get locked in as it were and become , well constants. My question is, what if we discard string theory -...

whats the turning point of (1-lnx)², x>2 is it a minimum or maximum. can someone help me

Can you gurus help me understand in a qualitative way the nature of the Coulomb barrier as it applies to alpha decay? I can intuitively appreciate the Coulomb barrier as it applies to anincoming charged particle, but resources I have been reading apply the same term to the barrier felt by...

I heard from many sources that quantummechanics is purely random in nature. Has this been demonstrated? If so, what is the proof?