A model is an informative representation of an object, person or system. The term originally denoted the plans of a building in late 16th-century English, and derived via French and Italian ultimately from Latin modulus, a measure.
Representational models can be broadly divided into the concrete (e.g. physical form) and the abstract (e.g. behavioural patterns, especially as expressed in mathematical form). Of particular importance in the modern context, conceptual models are central to philosophy of science, as almost every scientific theory effectively embeds some kind of model of the physical or human sphere.
In commerce, a model might instead reference a specific version or configuration of a product offering, rather than functioning as a representation of something else.
In taxonomic settings (e.g. biology, architecture, art) a model is sometimes a particular instance of a set of related entities (species, built structures, artistic compositions) chosen as a convenient reference point around which to build discourse; such a model is almost always chosen to typify some central tendency of the group, exemplify the group's defining characteristic, or reify the group's historical lineage.
Kinds of models include:
A mass of 1 slug is suspended from a spring whose spring constant is 9lb/ft. The mass is initially released from a point 1 foot above the equilibrium position with an upward velocity of square root 3 ft/s. Find the times at which the mass is heading downward at a velocity of 3 ft/s.
I found...
Hello,
I am trying to model an explicit dynamics model in Ansys, to study impact of different objects. I cannot figure out how to model a composite with several layers in workbench.
I have been trying to achieve this for over a week now. I was told that I can model the composite in Ansys...
1. The problem statement
I'd like to use Matlab to help me model and solve a simple 2D steady state heat conduction problem:
A square section duct is buried in the Earth some distance below the surface. This duct is at a steady temperature of 60 degrees C. I need to use the central divided...
I'm trying to prove why it is impossible for James Bond to open the parachute 2 seconds before impact and still land relatively unharmed. My argument is that there is no way a parachute can slow Bond from 190km/h to about 40-50km/h in 2 seconds.
I tried searching the web for information on...
Hi, I am looking to model the diffusion of a particle through 2 layers using the finite difference method in matlab. I already successfully have modeled this in a mono-layer configuration, however I am looking to code it through two layers.
I have two layers, one is 1 micron (1E-6) and the...
Hello,
I am trying to model a basic automobile suspension arm in 3 dimensions. The model consists of basically a triangle made up of 3 vectors a, b, and c. Vector a is "ground" and magnitude and direction is known. Magnitudes of vectors b and c are also known. So, I can write the following...
Given two bodies where GM/x^2=A and Gm/x^2=a, how might one model the acceleration of either bodies as a function of time?
A simpler version of the problem involves one of the masses being stationary (just for the sake of simplicity), so that GM/x^2=A and Gm/x^2=0.
A more complicated...
I want to model the results of collisions between minor planets over timescales of My and By. (I am NOT a scientist, just an observer).
Background
Years ago, the theorists did modeling of the solar system to see the impact that collisions had on the evolution of asteroids. The results were...
In EE when one has 40 transistor all agree that it is to complex for a person to understand without using computer simulation. In an economy with 7 billion people and millions of groups, organizations, corporation, governments most seem to feel that simple analogies are good enough to understand...
Hi guys, I'm new to the forum, I'm a mechanical engineer but running a project a little outside my comfort zone which is to do with optics.
I am trying to calculate the power density of a pulsed Nd:YAG laser but am getting in a muddle with the Average and Peak powers. The project is to model...
Basic premise: a pure tone sine wave can be modeled with a pendulum and the rate of amplitude decay can be manipulated with a friction coefficient.
So... does anyone know how this is actually done? In other words if you picked a pure tone (let's say middle C @ 261.6 Hz) initiated at a certain...
Okay, please don't ask me why I would want to do the following; I'll try to explain..
I am writing a program and already have a module for computing 2D rigid-body and spring-mass (with only 32-bit integers, no less) which I've modified from Box2DLite.
Now, for my application, I would like...
Homework Statement
This is an optimization problem but I'm having trouble modeling the question.
There is a sphere encased in a cone. The sphere has a fixed radius R and the cone has a variable height h and radius r. There is also a variable angle theta at the base of the cone.
Express the...
I am trying to model the RPM at which the turbo I plan to fit to my BMW will develop the desired pressure ratio.
I have determined air flow into the engine at the desired pressure ratio and have determined the rpm at which peak power and torque should arrive. I have also determined the size of...
I'm guessing it depends on how many factors/how unpredictable a subject is, what is it really? What makes mathematical finance so rigorous- requiring a phd in math/finance- while something like systems biology or pharmacokinetics only requires knowledge up to linear algebra?
Homework Statement
The problem can be found here: http://alex.fangsoft.net/math.pdf
I have completed Task #2, it is Task #1 that I am very lost on. Our teacher has really thrown us head first into the water with this one, I am very unfamiliar with differential equations and their...
Hello all,
I am a beginenr and I need help as to how to model sin(wt) in matlab?
how could i define the variale t ?
I would liek to have cases for different frequencies where w = 2* PI * f
and f is teh freuqency of excitation...
thanks for your help
Hi,
My differential equations professor wanted us to think about this problem:
How would you go about modeling the rate at which water raises on a paper towel dipped into a puddle with fixed water level.
I figure this would be a differential equation, but I'm not sure as to the form of...
The initial mass of fish in a lake was 7 thousand pounds on January 1st, 2001. Since the time, there was a 4-year moratorium on the harvesting on this specific type of fish. This species of fish reproduce at a rate proportional to the mass and by next year on the same date, there were 11.54...
Homework Statement
The initial mass of fish in a lake was 7 thousand pounds on January 1st, 2001. Since the time, there was a 4-year moratorium on the harvesting on this specific type of fish. This species of fish reproduce at a rate proportional to the mass and by next year on the same...
We have just begun this topic and I'm really confused about how to approach questions, is there any trick or guideline for doing so?
Ex: Consider an isosceles right triangle whose hypotenuse is the x-axis and whose vertex is on the y-axis. If the hypotenuse is 2 units long, we'd have...
Hi guys.
I want to model the pressure distribution in rolling process and convert the pressure distribution into equivalent nodal forces. How do I do it. Please guys it's urgent. Any links would also help.
Thanks
Hello! My question for you is regarding models of functions. I am in first year calculus and we are covering a lot of material on modeling functions given a set of data or a graph, etc. I partially understand the material, but the information is scattered in my mind and when I go to formulate a...
I am trying to replicate a JAVA based applet on MATLAB. Applet can be seen http://www.engr.colostate.edu/~allan/thermo/page6/EngineParm1/engine.html" .
The theory behind the functions of the applet is http://www.engr.colostate.edu/~allan/thermo/page6/page6.html" .
It is actually a finite...
Homework Statement
A certain virus spreads through an entire population of 1000. It is assumed that the virus spreads at a rate proportional to the product of the infected and the uninfected. k=.00005 and initial infected is 250. Write and solve the diff eq for this problem.
Homework...
I'm trying to model the I-V characteristics of a few diodes in LTSpice. Though doing the DC sweep I have in the picture doesn't seem to give me what I want. I'm sweeping from -80V (It's breakdown is 75V) to 2V, in 1V increments.
What kind of simulation do I have to run across the diode to get a...
Hello all,
I have questions regarding my understanding of NMR and the mathematics of it. If anyone would take the time to read this, I would very much appreciate it. Please bear with me, I am a beginner. Thank you!
First, there is the question on how to model this phenomenon. Up till now I...
Hey everyone,
This is my first-ever post on a forum, so my apologies if this is the wrong section or if this topic has been covered...
Anyways, I'm trying to design an optimized propeller/generator that will be in a closed pipe, but I have no idea what kind of software to use as I've never...
Hi guys, I'm looking for the following functionality out of a free, or cheap software. I'm very close using google sketchup but I appear to have hit a snag that nobody on their forums can figure out, so I come here.
I want to be able to make a simple 3D model (so far I've just been using the...
I'm trying to figure out how to enter this into my calculator and get a graph, but I think it may be underpowered.
I have a Casio fx-9860gii, to be clear.
The problem is:
y=0.0034e^-(x-515)/26,912
200 greater than/equal to x smaller than/equal to 800
Thanks for any assistance.
:-)
Hello all,
Ive never really worked with Acoustics before but have been looking into acoustic raditation, effects in cavitation, acoustic fields, sonar, etc. However, it has been pretty difficult to find any information on equations or modeling of the collision of the acoustic waves.
The...
Homework Statement
Consider a cylinder (roll) of paper rotating about it's axis. Paper density - \rho, cylinder length - L and cylinder initial radius - R_0. External torque - \tau(t) is applied in the direction of cylinder axis. Given initial angular velocity - \omega_0 find the evolution of...
Dear all,
This problem is on the modeling of an unfocused receiving acoustic transducer and compute the electric signal due to the pressure field. I have come up with this simple model in 2D. Basically, the transducer has a flat surface S and the surface is assumed moving in the direction...
Hi guys.
I just want to know how Modeling (Mathematical modeling), simulation and Engineering Design are related. Your views are welcome. Any references and links would be appreciated. I just want to know more about the Design Process and how different processes and techniques are used for...
Homework Statement
Hello all, I just have a quick question regarding the modeling of the following circuit (see attached).
I am trying to derive the equation for the voltage across the capacitor as a function of time. I come up with the correct result when the element polarities are the same...
Homework Statement
Homework Equations
I would like to know if my work is correct. I thought that the graph would be a sinusoidal, but there is a small irregularity in the middle.
Am I correct in using θAC = 90 deg and θAB = 36.8699 deg in solving for the constant angular velocity...
When I model a honeycomb type composite in workbench I tired modeling the core material as an orthogonal material type using solid tet elements and the aluminum face sheets as isotropic shell elements. I base the core material properties off of the honeycomb manufactures data for stiffness...
Well, I discussed with a classmate about the wonders of this cosmos, watching "Into the Universe with Stephen Hawking", the alien chapter, which told about concepts of alien life in exoplanets. So we thought about concepts of "Exouniverses". I use this term because:
Is it possible to model or...
I have been working on making a 2-dimensional physics simulation on my computer and am having a bit of trouble with collisions. I know that:
-horizontal momentum is conserved
-vertical momentum is conserved
-kinetic energy (both rotation and translational) is conserved (assuming elastic...
Good day!
Please help me with HFET model for Aim-Spice!
I have a problem with IV modeling...
VAX
vds 1 0
vids 1 100
A1 100 2 0 Mhemt l=0.3u w=150u
vgs 2 0
.MODEL Mhemt PHFET
+d1=0.03e-6
+delta=3
+deltad=4.5e-9
+di=0.01e-6
+epsi=1.0841e-10
+eta=1.4
+lambda=0.05
+m=3...
Does anyone know of a real system for which a collection of (weakly coupled) identical oscillators is a better model than it is for a solid?
Diatomic gas molcules are a possibility, but I'm really looking for a system of distinguishable oscillators, which no doubt dictates oscillators at...
I'm trying to understand how I could use simple circuit analysis techniques to model a charging battery in the circuit attached. The battery connected only to a power supply will want to sink up to about 1A starting out then will transition downward quickly to about 200ma. Then it will fall off...
This is my first post and I'm pretty much lost when it comes to linear algebra. I am a programmer and I am currently working on converting a 3D model format for personal purposes. I am having trouble figuring out an equation. If you want the background of what I am doing I'll be happy to explain...
Greetings. I am attempting to model the path of light through different vessels containing water. For example, water in a test tube (pyrex), or water in a quartz cuvette. I am looking for a program which can handle the properties of the container (glass composition) and the medium (water). I...
Homework Statement
How can one model the vertical and horizontal motion of a swing? The maximum height was 258 cm, the lowest 38cm and the horizontal movements went from 2.39m on the left to 2.44m on the right. The period was approx 2.5793 seconds.
(The data was hand collected, so it is not...
I'm having a lot of trouble getting my head around this topic.. I am currently trying to create a numerical model of traffic flow, which has worked out to be a nonlinear hyperbolic PDE. If anyone could explain the concept of the Riemann problem to me in lamen terms, it would be greatly...
Homework Statement
hi I am reading Guenther & Lee, "partial differential equations of mathematical physics and integral equations" on the
first chapter second section i think, on "Small vibrations of an elastic string" they give this argument:
1. consider a string of x length L, the string is...
Homework Statement
Derive an equation of the form y=ax^b to model the given data: (35, 0.01) (28, 0.03) (20, 0.1) (15, 0.3) (11, 1) (9,3) (6, 10) (4.5, 30)
Homework Equations
Well, I know the answer is y = (7790 +/- 1246)x^(-3.698+/-0.1036) because that's what LoggerPro spits out, but...