Physical Definition and 1000 Threads

I know,that my question is bizarre,but i m interesting for answer. To create formula,i mean,that scientist makes experiment and formula is result of it.And I have sometimes problem to understand,what physical formula means. For example:Average speed is simple to make scheme.Just speed...

I suddenly realized that the very notion of a directrix seems odd to me. (1) I don't know any physical significance of such a thing (2) How anyone came to define the parabola as such Any help? I read some older posts about the history of the directrix/focus definitions of the conic...

Hello, What is the physical meanining of rational and irrational numbers? In the same sense, what is the physical meanining of complex quantities? Thanks in advance

In the past I have worked with scalar and vecor fields. I get vector fields. at each point the field has a magnitude and direction. With tensor fields, from what I have seen in diagrams, each point has three vectors assigned to it, and they appear to be orthogonal to each other. What is the...

1a. Find the number of vibrational, rotational, and translational degrees of freedom of CH4 and CO2. 1b. Use the equipartition theorem to calculate the molar specific heat for hydrogen (in gas state). --- Attempt at solution: 1a. # traslational degrees of freedom (d.o.f.) is 3 for...

I am not a physicist or a mathematician but I would appreciate if one of you talented people could help me. I also do not know if I am posting this question in the right area I am interested in developing an exact formula for synchronizing sound to a physical motion. Video taped images...

I am wondering if anyone knows of research being done, or theories that are related to the actual structure of space-time as they are related to physical constants such as the speed of light, Planck's constant, and the cosmological constant. I'm far from being a expert, but I've been playing...

Hello friends. I simply couldn't find an easier way to explain what I'm looking for, so here's a drawing. And my questions are: 1. Does something similar even exists, and how is it called? 2. With the proper masses/ratios/calculations/whatever & control system, is this device able to...

Hello There, I'm a senior at the University of Illinois Chicago, studying mathematics and chemistry; I'm at the point where I need to become familiar with a computer programming language that will not only be useful down the road but help with the admission process into graduate school...

The discussion about the status of lorentz invariance, and as I wanted to twist it, in general, the physical and scientific basis for symmetries started to diverge in my posts so I started a new thread for this to comment more without contaminating the original thread. Thanks for the links...

Can the circulation about some closed (rigid) path in a force field be interpreted as the work done by the force field on the path over an infinitesimal time?

i have read about wigner rotation but i think i can't understand it well , i want to know the physical meaning of it .

What physical quantities are these differential forms in classical electrodynamics? I read the paper ofhttp://arxiv.org/abs/physics/0005084" (A gentle introduction to the foundations of classical electrodynamics: The meaning of the excitations (D,H) and the field strengths (E, B)). The...

Homework Statement at 20 degree celcius, the solubility of a solid substance x in water is 42g/L. There are 3 solutions containing x kept at this temperature: S1 contains 5.1g/L,S2 contains 39g/L, and S3 contains 57g/L.so, how to make a saturated solution containing 45g x per litre overall for...

Abstract This post introduces a holistic approach to the description of the physical reality. The solution, referred to as the Dynamic Universe (DU) [1], is based on a zero-energy balance of motion and gravitation in spherically closed space. The Dynamic Universe allows the derivation of all of...

at 20 degree celcius, the solubility of a solid substance x in water is 42g/L. There are 3 solutions containing x kept at this temperature: S1 5.1g/L, S2 contains 39g/L, and S3 contains 57g/L. if we want to make S1 saturated with x, is it possible that we can add an equal volume of S2 and S1...

Homework Statement A rigid container,maintained at 50 degree celcius, is evacuated by a vacuum pump. After this, some liquid n-propanol is introduced into the container. part of the liquid will flash off inside the vacuum,but eventually the system will settle into equilibrium. what is the...

I have maintained here several times , amid howls of objection from a few, that spacetime IS something more than a mathematical construct or that at least we should maintain an open mind about that possibility. I have been thinking WHY I have that view and a significant reason is the presence of...

Hi there, In all text of QM I have, they tells that the density operator is hermitian. But without considering the math, from the physics base, why density operator must be hermitian? What's the physical significane of the eigenvalue of density matrix? Thanks

I wasn't quite sure which forum to use for this, as it covers QM, relativity and geometric algebra, but I'm trying QM for a start. The Dirac equation can be expressed surprisingly simply in the Algebra of Physical Space, as has been shown by W Baylis, and I worked the same thing out...

Hello, I'm currently living in Florida, but I'm planning to stay at my aunt place in New York for a couple of weeks this summer. Also, I'm no longer living in the apartment where I was living and will be looking for one while staying there. I'm applying for jobs these days, and I'm wondering...

Homework Statement how can i have a feel of pressure ... i mean how much is 1 psi and how much is 10 psi pressure ... can you please give an example ! Homework Equations i think pressure = force / area but still i don't undersatnd how much is 1 Newton ... i mean i don't get a feel of...

I am having trouble clearly/completely understanding the main cause of a transfer of thermal energy into the environment as a result of a bond formation. In terms of a very simple, generic, exothermic reaction... What I know...I can picture the atoms coming together through electrical...

Given the volume of a sphere V is given by V=\frac{4}{3}\pi r^3 Taking the derivative of the V wrt r gives \frac{dV}{dr}=4\pi r^2 which is the Surface Area of the sphere: \frac{dV}{dr}=A_s Taking the derivative of As wrt r gives \frac{dA_s}{dr}=8\pi r which I don't recognise as...

Hi I'm trying to get an opinion if Mathematical Methods in the Physical Sciences by Mary Boas is a good book to learn physics mathematics with a background in Calculus. I've been seeing people like it as a reference book, not so much as a learning tool. Opinions? Thank you

http://www.eurekalert.org/pub_releases/2009-07/lu-pro070309.php Well, according to this article, at least. http://www.sciencemag.org/cgi/content/abstract/1174962 Just thought I'd share. Problem is, they didn't entirely describe high temp superconductivity. O well.

Currently we see to about 15 billions years, determining that to be the edge of the universe. Could that just be the limit of what we detect can travel? It experiencing "friction" or other obstacles along it's travels.

I was reading on the net about 800m distance running to try and improve myself in the event, and then happened to come across this ~ Yes I know this is common sense and again backed up by medical science's experiments on lactic acid build-up and also since the professionals are far from...

Homework Statement A uniform circular disk whose radius R is 40.0 cm is suspended as a physical pendulum from a point on its rim. (a) What is its period of oscillation? (b) At what radial distance r < R is there a point of suspension that gives the same period? R = .40 m g = 9.81...

Imagine, You have dug a hole clear through the Earth. From one side to the other. Don't ask me how, you just did. Let's pretend that the hole is totally perfect: Same diameter thoughtout, no cave-ins, and it somehow doesn't get hot or filled with magma in the center. It's just a clear shot of...

As I recall, Rovelli never published anything about DSR until August 2008, when he posted "A note on DSR" on arxiv (0808.3505). And he never took part in the discussion of whether GLAST spacecraft (now called Fermi) might or might not observe that high-energy photons are delayed. It...

This may be a stupid question or have a pretty obvious answer, but I can't seem to find one so I'll just go ahead and post :) I was looking at some empirical data for relationships defining (abstracted) values for ionization and recomination coefficients in gases as a function of electric...

For SU(2) rotational invariance there is a clear interpretation of what all the generators mean. They correspond to operators whose eigenvalues are some observable. The noether charges correspond to the x,y and z components of angular momentum. The casimir is just the total angular momentum...

Is it just me or do other people think the atkins physical chemistry book is absolutely detrimental for undergraduates? Unless one is sound in their physics, chemistry, and math and the student is using the book as a means to find out other perspectives on chemistry issues, atkins is not...

Like university researchers measuring the force of Ricky Hattons punch with a special bag, or when programs talk about the force of crashes and ballistic impacts like shells and so on. But force is the mass x the acceleration. That indicates how strong something had to be to accelerate that...

http://arxiv.org/abs/0905.2292 A new physical principle: Information Causality Authors: M. Pawlowski, T. Paterek, D. Kaszlikowski, V. Scarani, A. Winter, M. Zukowski (Submitted on 14 May 2009) Abstract: Quantum physics exhibits many remarkable features. For example, it gives...

I understand that reflected waves on a transmission line are a result of the constraints of Ohm's Law and Kirchhoff's Law at the transition points. However, I'm having trouble visualizing the physical cause for this. What is actually causing the electrons to flow in the opposite direction...

Apparently extensive music theory of European, Hellenistic and ancient world is beyond my current depth. However, it seems reasonable to expect that western musical notes have a substantive physical basis in addition to relative consistency and obvious physical parameters. Obvious...

Can anybody give example of a physical phenomenon which can be stated into a polynomial equation (cubic, quintic or whatever) and which has complex number solutions and those complex numbers have some physical interpretation? The reason for asking such question tagged in physics is that i...

Hi, I am interested in taking a complex analysis course. How useful is it to the physical sciences?

Homework Statement Hi guys, I have 3 questions on physical optics, I really don't know where to start or what equations to use. Sorry for the horrible drawings by the way http://yfrog.com/0dfigure1p 1) Coherent monochromatic light of wavelength, lambda, in air is incident on two narrow slits...

Physical Chemistry Help! Homework Statement Hello TT forum. Finals are coming up!...and i am having a hard time solving these stoooooopid physical chemistry problems. ..any help would be GREAT appreciated! These are the 4 problems i am having a hard time with. I put ======= to separate each...

I've recently purchased a book on Quantum Physics, and I'm trying to get the basics down. At this point in time, I'm reading up on how Planck proposed that oscillators can only oscillate at discrete energies as opposed to on any amount of energy (on a theoretical continuous spectrum). This came...

Firstly let me waste a bit of your time by explaining I have not done much with maths or physics for ages! So please forgive my stupidity. My question: What kind of physical force does the Earth's magnetic field exert on any object on earth? My calculations (very probably deeply flawed)...

I have read about how space-time is shaped by gravity - fine. Is there an underlying assumption that 3D space exists in the first place? (because that's where we live). If I were to place a 3D sphere of radius 1 billion miles into nothingness - would it hold up? I mean there is nothing to...

Hey. I currently have a copy of atkins physical chemistry, although it is fairly old (4th edition). I found it for $20 at a second hand bookshop and it isn't in the best of conditions, but it has done the job so far! Anyway, what I am wondering is, are the later editions (8th i think?) much...

Can you please give me links in forums, where I can correct grammar of the article by one to one sentence (i am not native speaker)? Maybe it is not necessary to find peoples with physical knowledge. Any other suggestions?

Can you give me links on forums, where I can correct grammar of the article by one to one sentence (i am not native speaker)? Maybe it is not necessary to find peoples with physical knowledge. Any other suggestions?

Hi, Can u point out physical interpretation of the complex permittivity? (ie. what can u expect from a material with \epsilon' = x and \epsilon'' = y ? what happens if y is very large etc. \epsilon = \epsilon' -j \epsilon'' thanks Krindik

Homework Statement You are given a meter stick and asked to drill a hole in it so that when pivoted about the hole the period of the pendulum will be a minimum. Where should you drill the hole Homework Equations T=2*pi*sqrt(I/mgd) The Attempt at a Solution So I use parallel...