Interaction Definition and 713 Threads

Homework Statement A person weighing 800 lbf climbs a flight of stairs that extends a vertical distance of 300ft. Calculate the work and power required for this process if it requires 3 min, 5 min, and 10 min. Homework Equations W=integral(Fds) Power=FV The Attempt at a Solution...

Homework Statement Denver's Mile High football stadium incorporates a system by which a section of stands can be moved to accommodate different sports on the field. The grandstand, which has a mass of 4x10^6 kg, can be moved a distance of 45 m on a thin film of water. The movable grandstand...

As time is considered the 4th dimension can we say the 3-d world to be floating(advancing forward in time) in the 4D. If so is every inertial frame has is own velocity rate(moving in the time dimension) in the 4-D. When you have 3-D world if you want to bring 2 objects in contact you can bring...

Hey, I've simulated a solid metal cluster of gold fcc100 And a surface Platinum in fcc111 using a classical mechanical approach. Do you think i could get the surface free energies(the ones to use in determining the Wulff shape) from periodic boundary conditions and if so how? I am really...

Homework Statement How would you expect the interaction to compare in the following situations, all of which occur in a A2 molecule. 1) interaction of two 1s Aos in H2 2)interaction of two 1s Aos in N2 3)interaction of a 2s and a 2px AO 4)interaction of two 3s in O2. The Attempt at a...

Hello there, I'm studying thermodynamics right now, and a question popped into my mind for which I haven't found a decent and detailed explanation so far. Say that we have a container filled with any kind of gas, and we can control the temperature of the wall of the container. If we increase...

I read this week in Schutz's description of Pound-Rebka experiment, which demonstrate that a photon also interacts with gravity, i.e measuring its redshift. My question, is more from particle physics, I mean a photon is the interaction carrier of EM, its chargeless and massles, so how can it...

Greetings In order to make a mathematical model of the forces that act on a mechanism, I need to use the formula for the force between two magnetic dipoles. It would have to be a complete formula, that should take into consideration, aside magnetic moment and environment permeability...

Homework Statement Which of the following reactions are forbidden and why? \pi^{0}\rightarrow\gammaHomework Equations None? The Attempt at a Solution I'm pretty sure that the decay doesn't occur (it's forbidden) but I don't know why. I know that it decays most of the time into two gammas...

Homework Statement I am trying to follow a derivation in Jackson - Classical ElectrodynamicsHomework Equations In equation 1.58 (2nd/3rd edition) of Jackson - Classical Electrodynamics he says that by using the fact that \mathbf{\rho} \cdot (\mathbf{\rho} +\mathbf{n})/ | \mathbf{\rho +n|}^{3}...

hi all. i am trying to calculate the interaction between two excited hydrogen atoms, using degenerate perturbation theory. but comes up a few problems, any helps will be greatly appreciated. the perturbation has the form: H`=e3/R3(XaXb+YaYb-2ZaZb) where the R is the distancee between two...

A textbook gives the following interaction Hamiltonian describing the interaction of an atom (having transition dipole moment \mu) with a photon whose polarization can be \epsilon_{1} or \epsilon_{2}): H = g \Sigma^{2}_{s=1}\mu\bullet\epsilons\sigma^{-}a^{+}_{s} + h.c. where \sigma^{-} is...

Richard Feynman writes, on page 97 of his primer of quantum electrodynamics, QED: The Strange Theory of Light and Matter, about the interaction of a photon and an electron. He writes: "One way this event can happen is: a photon is absorbed by an electron, the electron continues on a bit, and a...

Homework Statement Consider the Hamiltonian H=\alpha L \cdot S Where L denotes an angular momentum with quantum number l and S a spin with quantum number s. Work out L \cdot S |(ls)jj_{z}> direction. Hint: expand (L+S)2 and go from there. 2. The attempt at a solution I'm highly...

Is it "Information" or "Interaction" that "Observes"? First off, I know there are many questions on this forum in regards to "does consciousness collapse the wavefunction" and I admit that this is roughly the same question in a different way. I wanted to approach this in a new topic though...

How does the 'particle' view of the electron for example interact with the lattice of matter when matter is also a wave function? coming from the view that the wave function is a probability field for the particle, so if that is used wouldn't the same need to be done for all possible...

Do photons experience time? If they move at the speed of light then special relativity states that they do not, but then does that mean they do not move forward in time which means the distance they travel is instantaneous (thus it is infinitely fast), which we know is not true (as they move at...

I am trying to understand the behavior of blackbodies in interaction with each other. Conditions as follows. 1) There are two blackbodies, say B_1 and B_2, with corresponding temperature T_1 and T_2. 2) Initially T_1>T_2. 3) B_1 and B_2 have thermal contact only through radiation...

At what distance do 2 hydrogen atoms (not ions) begin to attract each other? No, this is not a homework question. I am 58.

i want to know how neutrinos interact with strong beam of laser , if laser beam is going in opp direction along a neutrino beam?

Do we already know enough about the Higgs to be certain that we cannot interact with it(i.e. exert any type of control over it, like we can with electrons) or is there room for discovery there? I was just pondering some implications of such an ability, and realized that I don't know if the...

Hi, I am self taught, and am very interested in learning more about magnetic fields. I have found this site with some great examples of magnetic fields (http://www.coolmagnetman.com/gallery/imageset.html). One of the examples (picture attached), shows a group of five magnets. One is placed...

Hi, a few lines below equation (3.1.5) Weinberg writes: "The transformation rule (3.1.1) is only possible for particles that for one reason or another are not interacting." I thought a lot about it, but don't see any possible reason. Can you help please? After a few lines he defines...

Sorry for a naive question. In EM textbook and QM path integral textbook, the action and Lagrangian in electromagnetic interaction are S = L dt = e(\phi – A v) dt ---equ.(1) But in QFT textbook, the action and Lagrangian density are S = L d^4x = A J d^4x ---equ.(2) As I...

Problem A well-insulated piston-cylinder assembly containing 5 kg of water vapor, initially at 540 C and 60 bar, undergoes a reversible expansion to 20 bar. The surroundings are at 1 bar and 25 C. (a) What is the entropy change of the system, and of the surroundings? (b) What is the final...

In order to explain the relativistic nature of magnetism, a book shows an example of linear procession of charges: positive charges in one direction and negative charges in the opposite one. It says that this is equivalent in the reality to a not charged current carrying wire. In a metallic wire...

Homework Statement In different (scientific) sites I find different values for MF of H-1 ranging from 0.3 to 0.6 Tesla. Isn't there a generally acknowledged value? what about H-2 and H-3 ? The Attempt at a Solution using the general formula I get 1/ 8 tesla, that formula it not valid...

Can someone please help me clarify these points: - Is this statement true? Cation tend to be smaller than anions because when an electron is removed from a neutral atom, the nucleus (+) would be held more tightly (contracts) . Anions tend to be bigger (add electron), and thus you have a extra...

Dear All, I have a question that is afflicting me and I would be glad if you can give me an answer. I have a dipole in vacuum put at a certain distance from the surface of a dielectric material. I know the entity of the dipole, I know the distance from the surface and I know the interaction...

In the free case,we decomposite the free Hamiltonian into the creation and annihilation operators, i just wonder why this ad hoc method can not be used to the interaction theory?

Hi I would like to ask that what makes a transparent medium transparent ? What happens when a photons of light passes through our atmosphere ? I suppose that visible spectrum of light passes through atmosphere without causing excitation of electrons of gases' molecules, but what happens when...

So this concept of H = H_o + H_int has been extremely confusing to me. Wikipedia offers the best explanation, but there a couple things that still confuses me http://en.wikipedia.org/wiki/Interaction_picture Why is the state vector in the Interacting picture defined as |\psi_{I}(t)> = e^{i...

Hey all. I was wondering what the interaction between Electric and Magnetic field lines are. For example, when you hold up a magnet against a charged electrode. I tried searching in google, but everything just turned up one or the other or how a moving charge makes a magnetic field and etc.

Gravity interaction is possible between: A.Electromagnetic radiations. B.Material objects. C.Both material objects and electromagnetic waves D.None Can someone tell me its ans with reasons?

Homework Statement Find the force of interaction per unit length between the upper and bottom halves of a cylinder of uniform charge density rho. Homework Equations Solution should be \rho^2R^3/3\epsilon_0 The Attempt at a Solution Frustrated cause I've solved this problem in...

Homework Statement A thin target of lithium is bombarded by helium nuclei of energy E0. The lithium nuclei are initially at rest in the target but are essentially unbound. When a Helium nucleus enters a lithium nucleus, a nuclear reaction can occur in which the compound necleus splits apart...

In electron ionisation, how does the electron beam transfer energy to the molecule being ionised? Is it via the interaction of the electric fields of the electrons in the molecule and the beam? If so, what type of interaction? And why is ionisation efficiency of the beam maximised when the...

what is the difference between a "mass state" and an "interaction state"? I've encountered these terms a few times with no explanation, and googling around turns up absolutely nothing. Can anyone give me a brief description of the two terms, suitable for undergraduate level? thanks.

What are interaction states and what are mass states? Which ones are physical states? Which ones appear in Feynman diagrams? Explain your answer. I have that an interaction state is the state of a particle before the Higgs mechanism and the mass state is after the Higgs mechanism has given...

For a project, I'm trying to describe the interaction energy between two particles suspended in water which contains ions. I seem to have the double layer effect worked out pretty well, but I'm having trouble with the Van der Waals contribution, or more specifically, with the choice of Hamaker...

Spin orbit coupling accounts for the relative motion of a magnetic moment interacting with an electric field. Is there a direct coupling of the magnetic moments of, say, the electrons in an atom as well? Does a magnetic field emanate from spin 1/2 particles in general? Thank you for...

How does an electron that passes near an atom (near, but yet not that close to the nucleus) lose kinetic energy and releases an x-ray photon with energy equal to the amount of the lost energy. Shouldn't this interaction be an elastic one? I am not talking about an interaction with any of the...

Doing some examples I came across the question: Can the following processes occur and if not, why not? Draw Feynman diagrams for the allowed processes. one of which was K(-) (u(bar) , s) + p → K(+) (u , s(bar)) + Σ(-) (d,d,s) I thought that the strange quark could emit a...

Talking to the point, I need to know how a free neutron interacts with light (or a photon). Or, if they do not interact, the reason behind it. The reason why I am asking this question: Assume that a free neutron is being hit by light. If I assume that light is an EM wave, I can conclude...

Please teach me this: Because perturbative QTF theory is an asymptotic theory,then when the series is divergent(the terms of series increase as the n(the number of terms) tend to infinite) I wonder whether the theory is meaningfull or meaningless. Thank you very much in advanced.

I recently read a post which stated that the particle-antiparticle pair can be created by the interaction of photons "2 GeV is a threshold for proton-antiproton pair production, for example through photon collisions" I want to know more on these types of photons, their classifications and...

This is really about challenging the understanding of "Time" in the physical sense. I would like to test the hypothesis that time is merely the manifestation of particles in their interaction to one another. It seems that time may be meaningless (and non-existent) in a one-particle system...

I'm trying to get a deeper understanding of how two particles such as protons interact with each other. In high school physics, I was told that they give off a field, which is felt by the charges, and then repels them. My first question is, if I fire two protons at each other head on (lets...

HI, I want to reproduce results from the article (attached). I need to get parameters of interaction between atoms of H2 and C6H6 for Morse equation. I easily got results of interation between MOLECULES H2 and C6H6, shown in Table S2 'The first-principles and Morse force field (eq.1)...'...

Sometime during the last couple of weeks, during which I've been doing a lot of poking around on this forum and various other sources on the internet, I ran across something to which, unfortunately, I have lost the reference. It may even have been off of a link somewhere in this (cosmology)...