Model Definition and 1000 Threads

Homework Statement Hi. I'm in high school physics, and as I'm only 2 months in, I still don't know much. We launched a model rocket as an experiment and I need to find the thrust after adding 100g of mass to the rocket's body. The engine is an Estes A8-3. My teacher told me that its thrust is...

Homework Statement The 3 state Potts model is defined by $$-\beta \mathcal H = J \sum_{r,r'} (3 \delta_{\sigma(r), \sigma(r')} - 1) + h\sum_r \delta_{\sigma(r),1},$$ with J > 0 to encourage neighbouring Potts spins to have same value and h orienting field. The spin like variables can take...

I am working on a thesis, but new to programming. What is the best and easy to use program that I can use for the work: Measurement and analysis of elastic scattering of alpha–particle and light heavy ion scattering using nucleon-nucleon interaction

http://phys.org/news/2015-07-cosmology-standard.html The most popular candidate for the elusive particles that give the Universe extra mass is Cold Dark Matter (CDM). CDM particles are thought to move slowly compared to the speed of light and interact very weakly with electromagnetic radiation...

I've been discussing this elsewhere recently. In my opinion Purcell's explanation in section 5.9 doesn't actually explain why an electron moves in a circular or helical fashion in a magnetic field: However this length-contraction explanation has been around for so long that's it's...

Homework Statement Consider the below network of spins, the spins numbered on the nodes of the diagram. The spins interact via the following Hamiltonian ##\mathcal H = \sum_{\langle i j \rangle} \sigma_i \sigma_j##, where the sum ##\langle i j \rangle## is over nearest neighbours and ##\sigma_i...

Hey guys the Idea of simulating the DSE with a program caught my interest but I just had a few questions regarding the DSE Is there a function that models the probability of finding an electron at a certain point ONCE It's BEEN FIRED FROM AN ELECTRON GUN? like an amplitude function squared or...

Homework Statement Over the last ~100 years, the average solar constant has increased by ~ 0.1 W/m2. How much would the Earth’s temperature change simply due to this increase in the solar constant? Homework Equations [L * (1 – a)] / [4 * e * sigma]) 1/4 = Tground L is the incoming solar...

A check my work question... Homework Statement Louis de Broglie tried to explain Bohr’s hydrogen atom electron orbits as being circles of just the right circumference such that an electron of the Bohr energy going around the circle will interfere constructively with itself. This seems to...

When reading about GUTs you often come across the 'Standard Model decomposition' of the representations of a given gauge group. ie. you get the Standard Model gauge quantum numbers arranged between some brackets. For example, here are a few SM decompositions of the SU(5) representations...

For low values of n, Bohr's model fails to reproduce the value of the square of angular momentum, and the repulsion angles But Bohr model is basically a planar model... so the question should be, if we solve the hydrogen atom potential in a 2D equation, is it still different? The eigenvalues of...

Homework Statement given one each of u types of candy, two each of v types of candy, and three each of of w types of candy, find a generating function for the number of ways to select r candies. The Attempt at a Solution I am not sure if I understand this correctly, but this is what I came...

Homework Statement Homework EquationsThe Attempt at a Solution Hello, I am trying to construct the model, but I don't know how to incorporate 3 steps. I tried making 3 step blocks, but the input for the transfer function will only take one line. Then I tried to use one step block and make a...

http://www.iop.kiev.ua/~obraun/fk-intro.htm#model Question? Why this model is discreet? As far as I see particles can have any position? Why then is written in the text then In the continuum-limit approximation we come to the sine-Gordon (SG) equation?

From the semi-classical Bohr model of the hydrogen atom the velocity of the electron in a certain orbit can be determined. With these velocities the electron's relativistic masses can be determined. With E=mc2 the energy levels are in agreement with those from the Bohr model. I know Bohr's model...

Homework Statement My problem is with the last line of the derivation. Usually, we take the rate of change of momentum (force) to be change of momentum divided by the impact time. But this slide of pp showed that the traveling time of the particle in the box is used but not the impact time. Why...

Celeste: A new model for cataloging the universe The roots of tradition run deep in astronomy. From Galileo and Copernicus to Hubble and Hawking, scientists and philosophers have been pondering the mysteries of the universe for centuries, scanning the sky with methods and models that, for the...

Its been suggested that the metastibility of the Higgs may lead to a new cyclic cosmology to replace inflation. http://arxiv.org/abs/1307.8106 Can anyone give a layman's guide to how this works and they propose to solve the problems of the big bang that inflation is supposed to solve: flatness...

[Mentor's Note: Thread Moved from EE Forum] This link has the picture, for some reason it wasnt showing in this post. http://i.imgur.com/TYlb32t.jpg Here is my problem, I am supposed to use this circuit and solve for Av and Rin. My problem is that I have solved for Av but I can't solve for Rin...

Problem: In analogy to the Bohr Theory of the hydrogen atom, develop a quantum theory of Earth satellites, obtaining expressions for the orbit radius (r) and the energy (E) in terms of the quantum number (n) and the other relevant parameters. A satellite of mass 1000 kg is in a circular orbit of...

Hi everyone, I want to build a car-model which should be good enough to study under-steer/over-steer and test various safety algorithms like ABS, TCS, ESP. Initially I made a quarter car model, here I could implement simple ABS,TCS. Quarter car model supports only longitudinal dynamics and is...

I was looking at building a fpv plane. I was wondering if anyone could help me with the basic equations i would need for motor sizing etc. Just how I would go about finding power required. Looking at about a loaded weight of about 5kg wingspan 2.5-3m. Not sure of speed maybe around 40-70kph.

ZapperZ submitted a new PF Insights post "Violating" Einstein's Photoelectric Effect Model Continue reading the Original PF Insights Post.

Homework Statement There is a diagram in a book that shows a water pump sending water down a hill that then rotates a water wheel. The water reaches the bottom reservoir and is then carried back up the hill by the pump to start the cycle again. Q1. Use this model to describe an ammeter...

Whats the best value of ##Ω_k## (Considering Planck 2015 results).I asked best value cause If you think our universe can be also hyperbolic so ##Ω_k## can be different then 1. I remember the relationship between ##Ω_k## and k is ##Ω_k=-k/a(t)h^2## or some sort of something like that.k is zero I...

Hi there. I'm having a hard time understanding the precise meaning of the so called "cosmological principle": My understanding of the general Big-Bang model is that far enough back in time the observable universe came down to something very small (compared to now), very dense, very hot... Ok, i...

Homework Statement 1) vs = 1 mV. Find v1, v2, v3 and vL 2) Model the three-stage cascaded amplifier by a single voltage amplifier model. What are the values of Ri , Avo, and Ro? Diagram: Homework EquationsThe Attempt at a Solution 1) v1 = 0.909 mV v2 = 9 mV v3 = 818 mV vl =...

Now after applying and removal magnetic field H=0 there will be residual magnetic domain in XYZ directions Is the Heisenberg Model at very low temperature express about the energy of the system with higher accuracy than Ising Model in the previous case ? and at high temperature is the Ising...

hi, i want to derive a model of digital control valve. i don't have physical valve with me. still i have to develop such a simulator which can behave the same as the digital control valve. the working concept of digital control valve is little bit different than normal control valve. here is...

1.In Abelian higgs model,we can come to the results that the gauge bosons acquire mass, implying the photons also acquire mass in this model；however,photons are massless in reality.How to explain this dilemma? 2.What does U(1) mean in this model?Does it correspond to some coservation laws,or...

From a recent thread: Is this true of gluons? Doesn't the color charge invert under CPT? (For example, a red-antigreen gluon's antiparticle would be a green-antired antigluon.)

Hi! I'm working on something that could potentially be pretty big, maybe even huge, but I am in need of some consultation and data to work out various details in effort to buildup the framework needed for my theories. Bear with me though... a lot of the questions I'm going to ask may not be...

Hi I m studying modelling the viscoelastic passive properties of vascular walls and there is question! Why does Maxwell andKelvin-Voigt fail to represent a solid? and also what steps are required from a numerical point of implementation point of view , are required to turn an elastic model...

In this paper (http://science.uniserve.edu.au/school/curric/stage6/phys/stw2002/sefton.pdf) the author describes the transfer of energy in an electrical circuit as follows: "To explain energy transfer we need to look at what is happening outside the wires. As a consequence of the surface...

Hi I am Ken. Nice to meet you. I would like to get some info on this synchronizing module. It has a 3 phase lamp for synchronizing an alternator. Any knows what's the theory behind that flashing lamp? what if the lamp blink very fast or blinking slow? the reason is frequency is out of phase but...

Not according to this paper. arXiv:1507.08279 [pdf, ps, other] A Test of Cosmological Models using high-z Measurements of H(z) Fulvio Melia, Thomas M. McClintock Comments: 22 pages, 1 figure, 1 table. Accepted for publication in the Astronomical Journal Subjects: Cosmology and Nongalactic...

The supposed discovery of the Higgs three years ago was widely celebrated. Nobel prizes were handed out and the mystery of the origin of mass is now explained. But does the Higgs actually explain mass at all? When thinking about the Higgs, I think it's best to ask these questions first: 1...

Jorrie submitted a new PF Insights post The LCDM Cosmological Model in Simplified Math (Part 3) Continue reading the Original PF Insights Post.

Hi all, I am new to the forum. I have a BS in Chemistry (1984). So I remember a little quantum mechanics. I am trying to wrap my head around cosmology. I started studying GR on my own about a year ago. It took me almost that long to understand tensors. This invariably lead me to start reading...

Just started the study Exotic Hadrons (like mixing of Charmonium states with tetraquarks etc.) and got confused with quenched & unquenched quark model. What are the major differences between these two models? What key factors I should keep in mind doing calculations with these models...

Here's the main problem. I'll like a function of distance with respect to time which moves the planets in accordance to Kepler's law: planets in orbit travel equal area in equal time. I use a blender, a 3D app that allows for path programming.

What is the "consensus" status of the existence of a lattice standard model? These two sets of notes don't seem to be in agreement. Wiese's 2009 notes http://www.itp.uni-hannover.de/saalburg/Lectures/wiese.pdf say "Thanks to a recent breakthrough in lattice gauge theory, the standard model is...

Homework Statement I am trying to solve the model analitically just for 2 sites to have a comparison between computational results. The problem is my professor keeps saying that the result should be a singlet ground state and a triplet of excited states, but when I compute it explicitally I...

Hi, Just to let you know my level of knowledge/ability, I studied a degree that included some dynamics, but that was nearly 15 years ago, so I'm rusty. I'm a games programmer, and I tend to understand code (or things that can be translated into code) more easily than hardcore maths equations...

More than 300 years ago Galileo Galilei began to revise the geocentric model and he defended the heliocentrism model, now that still use the geocentric model and helps to much, time (time, day, month and year are based on geocentric model), geometry (Euclid), math, the same system of...

If we restrict ourselves to a homogeneous, spatially flat LCDM universe model, the Friedman equations can be written a very simple form. Marcus posted several threads in a collaborative effort to develop the simplified approach. Here is a summary of the parts that seem the most informative, to...

I am viewing (through https://www.edx.org/course ) an introduction course to computational neuroscience. In the second lecture, the Hodgin-Huxley model is considered. I am going over some of the questions and have encountered a problem with one of them (a picture of the exercise is attached...

Hello Everyone, I'm currently making simulations in Solidworks and am confused. I have to double the force on a pulley and change the dimensions from the original pulley, in order to withstand the new force. My hypothesis: If I multiply all the dimensions by the cubed root of 2, then my...

Marcus pointed out this yesterday: http://arxiv.org/abs/1506.08073 Lie Group Cosmology A. Garrett Lisi (Submitted on 24 Jun 2015) Our universe is a deforming Lie group. ***************************************** This is a non pretentious title, so his solution probably passed unnoticed. Also...

what is the origin of the number of bound (N z /2 ) in the calculating of average in ensemble in Mean Field for the Ising model?