Modeling Definition and 609 Threads

Hope this finds you well... i am having a problem analyzing a simple model that consists of 2 rectangles intersecting. the creation of the rectangles, material definition, BC, loading conditions...etc is done. but first: how can i define one rectangle to be a rigid body? second: the vertical...

So I've been given a differential equation that models bacterial growth, p(t), and the concentration of critical substance, q(t), whatever that's suppose to mean. I've solved both of these and found that: q(t) = q_0 e^{vt} Where q0 is the amount critical substance at t=0. v is a constant. I...

Modeling with power functions. I have turned to every book i own on math from algebra to math encyclopedia to calculus ab book. I seriously don't know how to come up with a power function for a set of data. I don't even know any techniques. There are no zeros or intercepts to this set of...

I'm not sure where to place this, so please forgive me. As you know, an electron experiences a force of F = qVxB in a magnetic field and equating this to centripetral force, we can find the radius of the electron's path to be R = mv/qB Ok, that's simple enough. Now, I want to model an...

Hello! I am looking for a software that can build models and can imitate the action of that model. The model will be made out of rubber-bands, cog-wheels, weights and more... anyone knows of such a software? it is very important... thanks!

Something I've been tinkering around with... I am interested in taking a wire a a certain length, L. As this wire lays straight, I can display it graphically on a computer that it is laying straight. If at some point, I pull on the center of the wire to make an arc in the wire, I would like...

Does any of you have an idea of how to model the behavior of a bouncing ball with STELLA (ISEE Systems)? I have only been able to get my model to show correctly the first two cycles of the bouncing motion. My idea is to have STELLA to plot the first cycle and have a variable to multiply the...

Hi, I was wondering if anyone out here on a Friday night could help me understand population modeling. Here is what I have as a problem (this is pretty simple because my goal here is to understand the thinking behind the madness :rolleyes: ) - The population of a certain community is...

Have any of you tried to goober around with Maya before? I've been trying my hand at it lately and am learning a little (very little). Its kind of hard clicking back and forth between the work field and the tutorial screen. All the online tutorials seem to assume that you already have a firm...

For those of you who are interested in learning about air pollution dispersion modeling, I recommend that you read the following online articles at Wikipedia: Atmospheric dispersion modeling Air pollution dispersion modeling books Air pollution dispersion terminology Compilation of air...

I am trying to model gravity with vector field lines in Matlab. I can kinda do it with a 2D plot, but I can't quite grasp the "scale" field in the quiver function. I then tried to model in 3D vectors and I just made a mess w/ that. Below is my simple 3D and 2D code. Help w/ this code or if...

Hey, I have this homework thing where I have to model an object's motion through a viscous liquid. I'm to assume that the resistive force directed upward is kv. Now, I'm going to take the downward direction as positive and the up as negative.. Should my force equation be mg - kv = m(dv/dt)...

Hello Does anyone know how to model a ball (sphere) with mass spinning with an initial angular velocity that gets dropped on the floor with a coefficient of friction? And find the final angular velocity? I tried solving the problem but somehow I got a singularity. The idea I used was...

In a paper, I encountered a system modeled by six coupled first-order differential equations like so: \frac{dm_i}{dt}=-m_i+\frac{\alpha}{1+p^n_j}+\alpha_0 \frac{dp_i}{dt}=-\beta(p_i-m_i) , where i=1,2,3 and j=3,1,2. According to the paper, the system has a unique steady state which becomes...

If you wanted to model a filter in an airflow using CFD, how would you go about it? I imagine that an exact model of a filter would be way too complex to model and take vast amounts of time to solve, so there must be some kind of simplification? I was thinking that maybe some known properties of...

Turbelence and modeling of this phenomenon are areas of professional interest, in addition to CFD and fluid-structure interaction. CFD-online is an excellent reference source for topics in CFD. I came across their Wiki and thought this might be useful...

I'm trying to model a circuit. Part of this circuit is a guitar amplifier. I don't know what kind of circuitry is inside the guitar amp, it manufactures often list the input impedance in the product specifications. When they say input impedance, do they mean the impedance between the...

Hey, I'm trying to model the motion of a batted ball (the pitch, collision and the hit). However, I'm including air resistance and drag, which makes it that much more difficult. I was wondering if there's anyone that would be willing to help get my MATLAB files to run properly and maybe check...

Hey, I'm trying to model the motion of a batted ball (the pitch, collision and the hit). However, I'm including air resistance and drag, which makes it that much more difficult. I was wondering if there's anyone that would be willing to help get my MATLAB files to run properly and maybe check...

I'm modeling a chemical reactor and I have to solve a system of ODE's like that: dX/dV = a*X dT/dV = b*(dX/dV) - c*(T-T0) I've been a Matlab user for so long but I've never seen a solution of this kind of system. I've tried to solve using ode45 but it didn't work. I've searched in books...

Hi, We recently solved the hydrogen atom and one of our homework problems asks us to replace the coloumb potential with a gravitational potential. I have the potential as being V(r) = -\frac{GMm}{r} Where M is the mass of the sun, m the mass of the earth. I have calculated the Bohr radius to...

We had a project in PHYC 2050 to write an applet simulating a scientific model. Me and my partner chose the solar system, which was a step up from the other projects (ideal gas law, refraction :biggrin: ). We took into account inter-planetary actions and used a simple "assume force is contant...

I won't say who said it, but does this sound right to you? Dendrochronolgists on TV all say it so easy, you count the tree rings and the space in between, and that will tell you about the temperature and precipitation and how long the tree lived. Also: This sounds kind of dumb, but what about...

Modeling By Calculus?!? HI I AM A STDENT WHO REALLY EXCITED OF PHYSICS. ESPECIALLY A BOUT THE MATHS THAT APPLIED IN PHYSICS. SOMEBODY SAYS THAT WITH CALCULUS WE HAVE HAD A VERY POWERFUL TOOL FOR MODELING. I HOPE MANY PEOPLE WITH DISCUSS ABOUT THAT IN THIS THREAD SO WE CAN KNOW MORE ABOUT...

I am looking for some force field parameters for nonbonded forces between atoms. In most molecular modeling programs Lennard-Jones function is used to calculate Van der Waals forces where sigma and epsilon are constant values for a pair of atoms. But i cannot find them anywhere. Or if...

So I have this project where I need to write a report and code of some numerical method used in some specific area of physics modeling. The report deals mostly with the numerical method but requires that some specific physics application tied into it. An example would be the Crank-Nicholson...

Hello, I need to model a generic CEV re-entry, and was wondering if anyone could guide me towards a resource for mass properties (drag coefficients, mass, inertias, initial velocity, etc). Thank You Shaun

Need Physics model for Hiller system Have been working on a model helicopter for some time and need to mathematically model a Hiller flybar. I have basic understanding of physics and have been researching gyroscopes to model the system, but still am missing a few bits and pieces. Have the...

Dear fellow engineers, I resently posted my resume and got several reactions good for me bla bla... Question. Which modeling sofware (Pro-E, Catia, Solidworks) and which stress analysis (FEA) program is best and most used. I like pro_E. It seems that everybody is using something else and...

Okay, here is the problem, ; Remesh likes to run outdoors and ride his bicycle at the veledrome. He burns about 400 calories/h running, and 300/h riding his bike. It costs $6/h to ride in the veledrome. Ramesh hopes to develope a weekly exersise program that will burn 4800 calories, cost no...

YATP - Yet Another Trainlike Problem Sailboats A and B each have mass 60kg and cross the starting line at the same time of a race. Each has an initial velocity of 2m/s. Obviously from this, m1 = m2 == 60kg and vo1 = v02 == 2 m/s. The wind applies a constant force of 650N to each boat and...

"A home buyer can afford to spend no more than $800/month on mortgage payments. Suppose that the interest rate is 9% and that the term of the mortgage is 20 years. Assume that interest is compounded continuously and that payments are also made continuously. 1) determine the maximum amount...

Ok, I have this modeling problem that I cannot figure out how to setup. The problem is given: The population of mosquitoes in a certain area increases at a rate proportional to the current population, and in the absence of other factors, the population doubles each week. There are 200,000...

I was hoping that I could find help solving this problem. I've been working on it for a while and haven't been able to solve it correctly. So far I have: \frac{dQ}{dt} = r - \frac{rQ}{100} Where Q is the amount of salt, r is the rate in and out. I think that this may work for the...

if you model a RL-circuit, the correct answer should be L(dI/dt)+RI=V but why doesn't the "I" in "RI" have to be "dI"?

I am currenctly doing a project on the mathematics behid human interaction in the currency market. I am looking for a programmer capable of building a program to run simulations based on mathematical equations and other parameters which I will supply that can mimic a real euro/dollar market...

I am currenctly doing a project on the mathematics behid human interaction in the currency market. I am looking for a programmer capable of building a program to run simulations based on mathematical equations and other parameters which I will supply that can mimic a real euro/dollar market...

Hey-- I'm trying to model the bending of a beam due to electrostatic forces. (Femlab does offer this model on their website, but the module I'd need to run it costs $600!) I have no problem modeling a beam bending, and I have no problem creating a parallel plate capacitor, but when I...

Neutral Substance Monism -- Any Modeling Potential? The purpose of this thread is to ask what potential, if any, monism has for helping to model the nature of the universe, and for filling in certain gaps which we have no satisfactory answers for. Monism is the belief that the basis of all...

The average hours of sunlight can be modeled on 1.5\cos \frac {\pi(x-3)}{26}+6.5 where x is the number of weeks since the start of the year. Ok. so it isn't really the calculation questions which are getting me, unfortunately it is just the reading of the model.. Here are the 2...

I am having serious difficulty attempting to mathematically model an inline web manufacturing system that we are attempting to modify in house. The model would be a dynamic model that would simulate the current throughput of the machine as well as the modified throughput to justify the process...

I've been working on/off with problems of environmentally assisted cracking, primarily in the fracture mechanics side of things and on occation some damage mechanics work. As a continuation for this I started looking for plasticity models which introduce the effects of hydrogen directly into...

How can we Mathematicaly model(Mechanical) a system which is in the form of cube...like a box ...what are energy conservation equations set up for static and dynamic analysi.s...

I am writing a physics modeling program which simulates rigid bodies in a 3D world. I've come across the problem of properly implementing friction. In general, the magnitude of the friction force is the friction coefficient times the magnitude of the normal force, and the friction force...

Hi ! I've been using 3D modeling software like Ideas, Solidworks etc. for a long time ... but they have one deficiency ... price ! At times I've tried cheaper alternatives you can find from the net ... but always had to revert to these "dinosaurs" when some features haven't quite cut it etc...

a landscape architect plans to enclose a 3000 square foot rectangular region in a botanical garden. She will use shrubs costing $25 per foot along three sides and fencing costing $10 per foot along the fourth side. Find the minimum total cost. I started off this problem by finding the length...

Hi! I am doing a simple mathematical model of an airship. I need the data for air temperature, density and pressure for different altitudes. Could anyone give me any web address where I could find these data? I am not native to this field, so I don't know how do these quantities change with...

hi, I'm an undergraduate from the University of Newcastle Upon Tyne, and I'm trying to develop an accurate model of a launch of a saturn V rocket for a project. i have access to the technical specs like fuel capacities, consumption rates, etc. but i need help on some of the harder...

http://www.biosci.utexas.edu/IB/faculty/parmesan/classes/Eastl_Ntr_00.pdf

I am trying to model a star using the old shooting method technique. I've encountered problems after my very first pass of integration. I know that I need to use a multi-dimensional Newton-Raphson technique and i think that I've not done this correctly. Could anybody please try and explain...