Model Definition and 1000 Threads

Homework Statement Model for learning in the form of a differential equation: \frac{dP}{dt}= k(M-P) Where P(t) measures the performance of someone learning a skill after training time (t), M is the maximum level of performance, and k is a positive constant. Solve this differential...

A model rocket is constructed with a motor that can provide a total impulse of 27.5 N · s. The mass of the rocket is 0.173 kg. What is the speed that this rocket achieves when launched from rest? Neglect the effects of gravity and air resistance. i know that the equation is p=mv (vector...

Have atomic models been proposed that do not have overlapping N levels?

Problem Find the minimum energy of the hydrogen atom by using uncertainty principle a. Take the uncertainty of the position Δr of the electron to be approximately equal to r b. Approximate the momentum p of the electron as Δp c. Treat the atom as a 1-D system My step 1. Δr Δp ≥...

Homework Statement Calculate the characteristic impedance ( Z0) of the two port network shown below: Could you help me with this question please.Homework Equations The Attempt at a Solution

Not everyone likes the idea of Universe ​​created from a point singularity, so recently grows in popularity the cyclic model - that our Universe will finally collapse and use obtained momentum to bounce (so-called Big Bounce) and become the new Big Bang. One might criticize that we "know" that...

Homework Statement The simplest useful model for fisher comes from the logistic model for population growth, together with a harvest h which is proportional to the current population P, that is, h=EP, where the constant E is called the effort. E measures the fraction of the population...

The problem statement: I have to find the transfer function of a mass spring system. There are two masses in the system and 3 spring. I also have to find the state space representation and the model of the system. I have attached a image of my problem and my work so far. I think I found the...

I'm looking for some engineering types to have a play around with my thermodynamic model of an internal combustion engine and reply with any thoughts, errors they find, spurious results or anything else which doesn't seem quite right...

I was thinking that "eternal inflation" model deals nicely with the problem of the beginning of the universe. If I understand this model correctly, Multiverse is a boiling bulk of some sort of very dense vacuum, creating inflationary "bubbles" (baby Universes), finite from the outside but...

The other day I started what I thought would be an easy project of modeling what happens in a clothes dryer but I quickly realized I have no idea what equations to use for mass and heat transfer between the inlet air and the clothes in the dryer. I'm assuming they both depend on the reynolds...

Anybody ever heard of the broken stick model? If so, what is it used for besides species abundance in ecology? Basically, n-1 points are randomly distributed on a unit interval, creating n intervals of random lengths. The points are independent, uniform random variables on the unit interval...

Hello people, I'm working on a research project involving the modelling of a black body's radiation spectrum, and near the limits of the spectrometer, the intensity goes to zero rather sharply. I cannot directly say it is error from the spectrometer, because I simply don't know. However, I...

Hi, I am trying to gain a better understanding of the classical model of electrodynamics, so what I mean by this is, using the idea of dipoles and electron movement to understand electrodynamics. More specifically, I'm studying plane waves, and I can't understand why when a plane wave hits a...

In system with one electron total angular moment vector ##\vec{j}## is just: \vec{j}=\vec{l}+\vec{s} http://selfstudy.in/MscPhysics/BScVectorModelOfAtom.pdf In page 3 author draw a triangle. Intensities of the vectors are ##|\vec{l}|=\sqrt{l(l+1)}\hbar##, ##|\vec{s}|=\sqrt{s(s+1)}\hbar##...

Homework Statement Hi, my question is regardng a Coulomb model of an H atom specified with Hamiltonian operator, Hhat, by spherical coordinates of energy eigenfunction ψ2,1,-1 (r,θ, ∅) =(1/ 64∏a02)1/2 r/a0 e-r/2a0 sinθ e-iθ Principal quantum numer n = 2 orbital an mom l = 1 magnetic...

Considering d=2 or d=3, the Ising model exhibits a second order phase transition at the critical temperature T_c, where the system goes from an ordered phase (spins preferably aligned in a certain direction) to a disordered one. This is reflected by the behaviour of the susceptibility, similar...

I'm a little confused about what is actually meant by the JP = 1/2 + octet. I'm pretty sure it means the particles must have spin 1/2 in the ground state (l=0) and an even parity but what I'm confused over is the absence of an sss, uuu or ddd state. I understand that this would give I3 = 3/2...

Fact: The refractive index depends on the medium. Also, in general, to study the pulse propagation in a medium, there is a governing model equation (e.g. Non linear Schrodinger equation). My question is: Will there be any relation between the model equation and the refractive index? Why...

The inductor below is conducting an arbitrary current, with the switch on. Suddenly the switch is set off and and voltage over the inductor raises to the negative infinity according to Vl = L*di/dt However, voltage is defined as energy per charge. V=J/C The energy stored "in" the...

Homework Statement The ground energy can be approximated as E_{1}^{(1)}\approx-\frac{4b^2}{a_0^2}E_R Find the largest value of b that would be consistent with the ground-state energy of a hydrogen atom that agrees with the predictions of the Coulomb model to one part in a thousand...

Homework Statement calculate current and voltage amplification The Attempt at a Solution Conversion to h parameter model, and this is my working step, https://www.filesanywhere.com/fs/v.aspx?v=8b6b628b5e646faf6e9b

I'm trying to come up with a good definition for model: X is modeled means x exists at time 1 and point 1 and has direction y, then it will exist at time 2 and point 2. Of course there are different types of modeling, for example, sometimes particles decay into other particles. Let me...

As usual, the interpretation is still unclear, but I think it is an interesting effect. LHCb studied the angular distributions in the decay ##B^0 \to K* \mu \mu## and presented the result at EPS2013. In one variable (called P'5) in two bins, a large deviation was found (3.7 sigma in one bin)...

Good evening, I've been trying to wrap my head around this problem for some time and I just can't seem to get it straight. What I am trying to achieve: I want to program a recursive model that calculates the position of a moving body in a fluid after a certain time. What i have done...

What is a good test for hypothesis testing of a complex deterministic model? What I'm doing: I have a complex system of nonlinear differential equations. I must solve them numerically. There are about 22 input parameters that I have rough physiological ranges for and I use a genetic...

Homework Statement consider all those capacitor is a short circuit for the ac current. I am to find i) Input impedance, ii) output impedance iii)voltage gain, Av = Vout / Vin iv) current gain, Ai = Iout / Iin The Attempt at a Solution So i first draw the H parameter model...

Homework Statement Car Dynamics f(t)→ \frac{\frac{1}{M}}{s+\frac{D}{M}}→y(t) Applied Force Velocity Homework Equations M=1,000 kg and D=1000 kg/s Where f(t) represents the input force and y(t) is the output velocity. M is the Mass and D...

Am I right in saying that in a Hydrogen atom when an electron jumps from the second orbit to the first one the energy change is more than any other possible jump (when the jump is not to the first orbit). The calculations seem to support me but it doesn't feel right.

I am currently working on a prediction problem using generalized linear model, My goal is to get the prediction distribution of the response variable. I read a thread (https://stat.ethz.ch/pipermail/r-help/2003-May/033165.html) saying the prediction uncertainty of a generalized linear model...

Hamiltonian ##H=-J\sum_{\vec{n},\vec{m}}(S_{\vec{n}}^xS_{\vec{m}}^x+S_{\vec{n}}^yS_{\vec{m}}^y+aS_{\vec{n}}^zS_{\vec{m}}^z) ## If ##a>2## is that behaves like Ising model? For example in ##2d## lattice is critical temperature of that system ##T_c \approx 2.269##?

I posted this question in an another forum but I didn't receive any answers, so I'll post it here again: Do all the fundamental particles in the Standard Model (61 fundamental particles) exhibit wave-particle duality? From my understanding, a photon acts more like a wave than it does a...

Hi all Here, I attached a figure presenting the Lorentz-Drude function. The resonance number is clear from the m in the equation. But I like to know if the number of poles in Lorentz model is the same as the number of resonance or not. I am confused. I would be very grateful if you can help me...

Hi everyone, at my university (Computer engineering) we are studying the small signal model, but i didn't understand the practical application, i mean, why and when should it be used ? For example at home i usually make electronics circuits, so i wanted to know how can i use the small signal...

Here is the question: I have posted a link there to this topic so the OP can see my work.

Can someone help me with this question. Let us define a Markov hidden model with 2-states A and B, such that P(X0=A)=0.6,P(X0=B)=0.4,P(X1=A/X0=A)=0.3,P(X1=B/X0=B)=0.8 what is the value of P(X3=A) ??

Unity hypotenuse model. As a worldline Shown in Fig. WL. http://imageshack.us/photo/my-images/832/29j2.jpg/ Pythagorean treatment shown in Fig. P. http://imageshack.us/photo/my-images/827/8ggf.jpg/

In quantum Heisenberg model \hat{H}=-J\sum_{\vec{n},\vec{m}}\hat{\vec{S}}_{\vec{n}}\cdot \hat{\vec{S}}_{\vec{m}} ##J## can be obtained from dispersion experiment. For large spin ##S## even classical Heisenberg model is good for description of Curie temperature for example. Is that with the same...

Hi, I have a 'simplified' equation of the magnetically suspended ball. a = g - (i/h * M) where a - actual acceleration of the ball. h - distance from the magnet. g - gravitational acceleration, to keep it simple let g = 10 M - mass of the ball 0.05 kg i - current through the...

I wanted to know if there is a mathematical model to know the force with which a source of a magnetic field attracts or repels another source of magnetic field. For example, the mathematical model for the electrostatic force a charged particle exerts over another charged particle is: F =...

http://www.sciencemag.org/content/early/2013/05/29/science.1235768 This is the result of fine-grained mapping of the gravity anomalies on the moon. They propose a bulls-eye model of impacts to account for the anomalies. I'm not competent to judge. The idea appears interesting to me.

A little backstory - I work in a warehouse where my job is to quickly and accurately pick products from the shelves to ship out to the stores. Recently, I've gotten a talking to from my supervisor regarding my accuracy. The standard here is that you must be at a 98% accuracy or you will get what...

Hi everyone I have trouble with this task Homework Statement the specific heat cv is given by c_v =\frac {N_A k_b \hbar^2}{{\Omega_D}^3 {k_b}^2 T^2} \int \limits_{0}^{\Omega_D} \! \frac {\Omega^4 exp\frac{\hbar \Omega}{k_b T}}{{(exp\frac{\hbar \Omega}{k_b T}-1})^2} \, d\Omega I...

Hello. I am currently studying scattering theory in detail for my BSc thesis, and I'm starting with Rayleigh scattering. I'm following Scattering of electromagnetic waves: theories and applications by L Tsang, J A Kong and K-H Ding, which is pretty much what I like in a science textbook...

My model is a lever on a table top. One arm is horizontal on the table, while the other arm is raised at an angle alpha. I'm assuming the weight of the horizontal lever (F) acts at its center of gravity at a distance f from the pivot, while the weight of the raised lever (W) acts at its center...

Considering the Nearly Free Electron model of solids, where we assume the valence electrons of some one dimensional(!) solid to move in a weak, periodic (with respect to the solids lattice constant) potensial. We may derive (which I assume you are familiare with, and will not do here) the...

I am currently working myself into black hole physics and I am interested in their possible quantum geometric description by means of LQG. Can anybody please tell me good sources to start with? Since black holes were studied in this framework for a longer time, what is the most recent...

Dear engineers and physicists, I would like to ask you a question about Component Mode Synthesis (CMS), which is the topic of my bachelor thesis. My primary resource is the classical AIAA article "Coupling of Substructures for Dynamic Analyses: an Overview" by Prof. Craig. For now I am...

I don´t continue the other threads because I can´t post a new thread in them. It is a very basic question. The strand model deduce GR, quantum physics ( Dirac Equation), thermodynamics, but it must deduce really QFT with GR incorporated, not the separate theories. The final theory must be a QFT...

I'm currently reading about the parton model and deep inelastic scattering. As I've understood it was observed that when protons collided at high energy very little transverse momentum transfer was observed, while when electrons were collided with protons transverse momentum transfer was...