Physical Definition and 1000 Threads

In both classical and quantum mechanics, there's a lattice called the logic of the physical system. In CM, it's the set of all subsets of phase space. In QM, it's the set of all closed subspaces of a Hilbert space. Sloppy presentations of this subject say that the members of the logic represent...

Edit: Here is the short (but more confusing and less rigorous) version of what I wrote below: For something to be considered a "law" it needs to make predictions which can then be tested, and if they are proven then it is considered law. However, scientists have been looking at the nature of...

I have to give a brief presentation on the evidence for pairing in atomic nuclei. One of the items of evidence I will talk about is the difference in binding energy between even-even and odd-odd isobars. For instance, here I have plotted the atomic masses of a range of even-A isobars A = 40...

I once saw three very large transformers in a fenced area smaller than a typical substation fencing. They were close enough to read some numbers on a metal nameplate which gave a list of about 6 primary tap voltages in the 12000 to mid 13000 volt range. There were some other stamped numbers...

It's a fundamental principle. But *why* does it have to happen? I can easily intuit why conservation of energy has to happen, and I can also intuit why conservation of mass has to happen. But with conservation of momentum, I can't intuit why.

In lieu of my previous question, (https://www.physicsforums.com/showthread.php?t=494393), which seemed a bit tricky to answer (!), I will simply ask the deeper physical question that lies at its base. That questions is whether there are any physical phenomena (temperature, pressure...

I'm trying to understand why various statistical distributions are so common. For the most part, all I can find online is how to calculate and manipulate them... I did finally find a couple of refs that helped with Gaussians, this being one: http://stat.ethz.ch/~stahel/lognormal/bioscience.pdf"...

Are there any applications of the Jordan Normal Form of a matrix in physics? If so, please explain?

http://img196.imageshack.us/i/unledup.png/ So we have a physical pendulum. It has a mass of m=200 g and radius 10 cm. It's suspended from point O at a distance h=8 cm. from center C. It is displaced 0.1 rad and released from rest at t=0. I'm struggling to find the mechanical energy of this...

I am new to this forum. Although physical chemistry only requires calculus 3 (which I'll have taken regardless), many people are saying that I would be better off taking more math than that before taking physical chem, since I wouldn't have to learn as much that's new. I've been recommended...

Pardon me if this is a really silly question, my knowledge of field theory pretty much only comes from Condensed Matter. However, I know, before RG, QFT had a big problem with integrals blowing up unless you assume some cut-off frequency exists. My question is, what is WRONG with a cut-off...

Homework Statement I'm talking about the probability density plot of the harmonic oscillator. Is there some physical meaning to be extracted from this? Here's a link that contains the drawing of what I'm talking about http://hyperphysics.phy-astr.gsu.edu/hbase/quantum/hosc5.html...

Suppose in whatever physical theory we are using, our derivative does not satisfy \nabla_X g=0 for tangent fields X. Of course, this means that parallel-transported vectors do not preserve their length. But what would this look like physically? Perhaps there are various consequences which...

Alright so I know the common answer: Enantiomers - same chemical and physical properties Diastereomers - different chemical and physical properties In lecture, our professor said that enantiomers can have different biological effects. I was confused because, as he had said earlier, they have...

When you solve the motion equation x=x_0 +v_0t +\frac{1}{2}at^2 you get two answers for t. One being a negative due to the quadratic. What is the physical interpretation of this? Its driving me nuts.

Homework Statement The dissolution of 5.25 g of a substance in 565 g of benzene at 298 K raises the boiling point by 0.625°C. Note that Kf = 5.12 K kg mol-1, and Kb = 2.53 K kg mol-1, and the density of benzene is 876.6 kg m-3. Calculate the freezing point depression, the ratio of the...

Homework Statement (2xy-5)dx+(x^2+y^2)dy=0, y(3)=1 (2x+y^2)dx+4xy dy=0, y(1)=1 x^3y'+xy=x, y(1)=2 y'(t)=-4y+6y^3 We're doing these in 2nd yr engineering Math and I have heard the Lecturer say they are useful across all disciplines. I've heard him suggest RLC circuits, springs with...

1. A 17.7 kg block is dragged over a rough, hor- izontal surface by a constant force of 187 N acting at an angle of angle 33.6 above the horizontal. The block is displaced 46.5 m and the coefficient of kinetic friction is 0.199. Find the magnitude Work done by the force of friction...

Hi all, I'm looking to control two outputs using (3) 12 V coil relays, with the SOP of the truth table listed as below: A' B C' + A' B C simplified to: = A' B ( C + C') = A' B ----> Y0 A B C' + A' B C' simplified to: = B C' (A + A') =B C' ------> Y1 The problem I am having is...

Hi, Hopefully this should be a simple and quick question. I've seen many calculations done with \hbar = 1. If I want to convert back into physical units, what is the corresponding transformation? I know wiki gives a description of...

hi guys,does anyone knows what is the physical interpretation of second(third, fourth,...) derivative?

We did an experiment using the physical pendulum to measure gravitational acceleration g. A graph is shown in this link: http://i593.photobucket.com/albums/tt20/omicgavp/measuringggraph.jpg" A nonlinear (possibly chaotic) trend can be seen in our graph even though we assumed small-amplitude...

Are they different in any significant ways? Are they frequently confusing? For whatever reason, I find pchem books somewhat hard to read (for now) because something with the notation is confusing me. Statistical Mechanics books are much more readable. Okay, for some reason, I understand things...

How would you describe the intersection between phase space and space-time?

Homework Statement This problem I have been set is to find real life applications of divergence theorem. I have to show the equivalence between the integral and differential forms of conservation laws using it. 2. The attempt at a solution I have used div theorem to show the equivalence...

Hey all, My question pertains to interior metrics, for example the Schwarzschild interior metric given in post #5 of https://www.physicsforums.com/showthread.php?t=323684 The radial derivative of the first term, the dt^2 coefficient, matches the radial derivative of the Schwarzschild...

The difference between Enthalpy and Heat transfer is the term vdP as dH-dQ=vdP What is the physical significance of the term vdP? :rolleyes: Wherever an article describes the difference between enthalpy and heat transfer, it is stated that heat transfer and enthalpy are same at constant...

Hello all, I am new to these forums and just registered. I plan to be an active participant on here and reciprocate the generosity I've observed in other threads. Im looking for a certain "material" that can satisfy this list of criteria that I've put together. I'm pretty sure that I am...

Warning: I'm not a practicing chemist. Answers in as-simple-as-possible language (but not oversimplified!) would be greatly appreciated! I'd like to know if the chemical properties of a solid can be affected by conduction band electrons. I assume that, in the majority of cases (and perhaps...

What's the difference between a physical Law and a physical theory? thanks

Homework Statement A pendulum is constructed using a thin rod (m1 = 2.0 kg, L = 1.0m) and a uniform sphere (m2 = 1.0 kg, R = 0.50 m). The period in "s" for small oscillations is: a) 1.5 b) 1.7 c) 2.0 d) 2.2 e) 2.5 Homework Equations T = 2pi *sqrt(I/mgd) The Attempt at a...

I have a Question: When the imaginary unit, i, is factored with time, t, in the Lorentz Transformation, or when the Hamiltonian is factored (as when Dirac created his Creation and Annihilation Operators,) and i is factored with the momentum, p, the iFactor is always factored with time, energy...

It seems like a problem that a physicist would need to solve, but I can't wrap my head around the physical interpretation of it. http://exampleproblems.com/wiki/index.php/CoV7 Also, why do they use u=c*x2? What is c in this case? It says "classical" so it can't be the speed of light, right?

Homework Statement What are the energies and wave functions for the quantum mechanical model where V = infinity for x less than or equal to 0 and V = kx2/2 for x greater than or equal to 0? Homework Equations 1-D particle in a box E = (h2/8m)(n2/L2) Harmonic Oscillator E = (v +...

It'll be a long one, but I'll try to make it as short as possible. First, I should give a brief introduction to the education system in the country I come from. Perhaps you've heard of the Bologna process in Europe; well, officially, we've accepted the system, but there are some differences...

Hello, I have recorded voltage signals (in the time domain) using standard electrophys amplifiers. The voltage is that of an electrode inserted in a plant stem as charged objects are brought close to, then into contact with the flower. I was wondering about the significance of the time...

Hi guys. What is really the need for complex numbers? Is there any physical meaning associated with it?

Homework Statement Can this function be a wavefunction of a physical system with finite potention energy: \psi(x)=\frac{A}{\sqrt{x^2+b^2}}Homework Equations noThe Attempt at a Solution The ans is YES. 1)it is continuous. 2)its derivative also continous. 3)It can be normalized, as it tends to...

Hey! I have some dumb-smart question Does 1D line have physical width? My logic says that mathematically you can go smaller and smaller,but I see there being a problem with 1D having infinitly small width in physics. If 2D object has infinitly many 1D lines that would suggest that 2D...

Homework Statement meter stick pivoted at point a from its center and swings as a physical pendulum. At which values of a gives you the shortest period of oscillation...1m, .2m, .3m, .4m. .5m Homework Equations T = 2pi*Sqrt(I/mgh) The Attempt at a Solution the shortest a should...

Can anyone tell me the physical law which is behind certain physical effects? 1. Resonance 2. Adhesion 3. Heat strain 4. Lever effect 5. Surface tension 6. Cutting/Bending 7. Evaporation 8. sublimation 9. Weissenburg effect 10. Torsion It would be really helpful for my research...

So I know what they are and I've been given some really vague and weak interpretations, but I want to build up my intuition and know more about the specifics of curl and divergence. To my understanding now I know that curl is similar to a paddle wheel spinning in a direction dependent on the...

1.the Schrodinger’s cat on test 2.wave - particle two-phase nature 3.entangled state 4.God does not play dice 5.the Bell inequality Please advice about the above statement should be how to write correctly?

Homework Statement Use the “virial equation of state”. Measurements for Ar gave B = -21.7 cm3/mol and C = 1200 cm6 /mol-2. Assuming that Ar is a van der Waals-type gas, what are the values of “a” and “b” in the corresponding van der Waals equation of state Homework Equations PV= RT(1+...

Hi. I did well in calc 1, but I got a C in calc 2. I also took both calc 1 and 2 about five years ago. I feel I didn't do well in Calc 2 because i didn't try, not because I was incapable of understanding, but I honestly have NO IDEA what calc 2 was about. However, Physics 2 (with calculus)...

An old QM exam question asked for consideration of a two-level quantum system, with a Hamiltonian of H = \frac{\hbar \Delta}{2} ( {\lvert {b} \rangle}{\langle {b} \rvert}- {\lvert {a} \rangle}{\langle {a} \rvert})+ i \frac{\hbar \Omega}{2} ( {\lvert {a} \rangle}{\langle {b} \rvert}- {\lvert...

Freidel will be giving a talk in the online seminar ILQGS, about Relative Locality---the subject of this paper: http://arxiv.org/abs/1101.0931 The principle of relative locality Giovanni Amelino-Camelia, Laurent Freidel, Jerzy Kowalski-Glikman, Lee Smolin 12 pages, 3 figures (Submitted on...

Hello everyone, haven't been here in a while. My tutor asked me wether I wouldn't be interested in writing a smal program to illustrate one particular case of 3-body problem. I definitely would be, it's just that I've never written any application displaying anything. Numerical calculations...

I have read that many tea masters insist that when infusing a tea that requires less-than-boiling water, you should first let the water reach a full 100 degrees C and let it cool back down to the target temperature, rather than take it off the burner as it is approaching boiling. I think it was...

I am an undergraduate student who wants a good, easy to understand, book for physical chemistry, specialized on topics like equilibrium, kinetics, etc. Please recommend some good books, which have the concepts explained thoroughly.