DO NOT USE THIS TAG just because the involved physics is based on a model. All physics descriptions are inherently model-based. This tag is reserved specifically for addressing model development, validity, simplification, or other meta-model questions.

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3answers
257 views

How long does it take for an electric car to go from 0 to 60 mph?

I found the freefall motion equation which describes terminal velocity of a falling body, but I can't find a similar equation for a vehicle subject to constant traction force, so I tried determining ...
7
votes
1answer
1k views

physics of wet hair

I'm curious about the physics behind the clumping of wet hair. More specifically, how the amount of water in hair and distance between hairs affect the clumping process. I know intuitively that when ...
0
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2answers
65 views

Should theory be the appropriate term? [duplicate]

Should theory be the appropriate term? I mean, for example, because of the quantum field theory we have been able to find the subatomic particles that it theorized and make the Standard Model. Why ...
0
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0answers
19 views

model for flexible stick

I'm trying to model a flexible stick with a partial differential equation. I want one of the ends to be fixed and the other end to swing. Do you guys know of any good models I can use? Any ...
28
votes
7answers
9k views

Why don't electrons crash into the nuclei they “orbit”?

I'm having trouble understanding the simple "planetary" model of the atom that I'm being taught in my basic chemistry course. In particular, I can't see how a negatively charged electron can stay ...
2
votes
1answer
87 views

Identifying an optics equation in a code refactoring project

I apologise if this a somewhat naive post. My knowledge of optics is limited, and I am learning on the job, so to speak. I'm a computational biologist, dabbling in a bit of physics. I'm currently ...
2
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2answers
43 views

Sampling a distribution (from a galaxy model)

I am reading the following article: http://www.kof.zcu.cz/st/dis/schwarzmeier/galaxy_models.html and am currently at section 5.6 (positions of bodies in a galaxy). I am trying to redo the simulations ...
0
votes
2answers
149 views

Why would an electron in an orbit be accelerating continuously and would thus radiate away its energy and fall into the nucleus in a classical model? [duplicate]

I was reading this answer by madame anna v: You are right, the planetary model of the atom does not make sense when one considers the electromagnetic forces involved. The electron in an orbit is ...
-3
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2answers
170 views

The nature of theoretical models

Mathematics is exact. It is a beautiful language that allows us to express quantities that aren't possible to be represented physically. We build theoretical models of physical systems that work out ...
1
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0answers
36 views

Which model of computation can be viewed as being extended by the currently most relevant models of quantum computation?

Which model of quantum computation resembles most closely the attempts of implementation currently being made? And which non-quantum model of computation is the conceptually closest one to the above ...
7
votes
1answer
88 views

Are there models/simulations of antigravitational antimatter-galaxies?

In the comments to another question's answer, I started wondering: Assuming antimatter possessed negative gravitational mass§ (which is not proven impossible to date, though deemed unlikely), ...
2
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1answer
83 views

Can all theories of theoretical physics be generalized to any (arbitrary) number of dimensions?

Please explain from: mathematical point of view "laws of mathematics", and, physical point of view "laws of physics"? Or is there any bound on number of dimensions?
-3
votes
1answer
76 views

How can we depend on the mathematical axioms that break down at the nano-level? [duplicate]

Mathematics "makes sense" at our scope of view. For example, gravity seems to obey the fact that it accelerates at a rate of 9.8 meters a second^2. However, when an object drops, the force of gravity ...
13
votes
7answers
427 views

Macroscopic laws which haven't been derived from microscopic laws

Can you think of examples where a macroscopic law coexists with a fully known microscopic law, but the former hasn't been derived from the latter (yet)? Or maybe a rule of thumb, which works but ...
5
votes
1answer
470 views

't Hooft for laypersons

I have looked at some of 't Hooft's recent papers and, unfortunately, they are well beyond my current level of comprehension. The same holds for the discussions that took place on this website. (See, ...
55
votes
7answers
7k views

Why do people categorically dismiss some simple quantum models?

Deterministic models. Clarification of the question: The problem with these blogs is that people are inclined to start yelling at each other. (I admit, I got infected and it's difficult not to raise ...
28
votes
3answers
1k views

Floating a ping pong ball in the air just using a pen!

Caution: Apparently this problem is harder than it seems! There is a well known phenomena, which I first learnt about when I was a 10 years old kid. You can levitate a ping pong(or whatever ...
1
vote
1answer
117 views

How can I validate a numerical model using an analytical solution of the same scenario?

In the course of my research project I have been tasked with validating an acoustic model, however I am having trouble conceptualising what I am supposed to do. I have found an analytical solution for ...
1
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1answer
160 views

Fitting a circuit scheme to a simpler model

I have to simulate the electric field within a gas filled discharge gap generated by a radio frequency voltage generator. The circuit, provided to me by the experimenters somewhat far away, is given ...
1
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2answers
79 views

Any noise slowly starting to take effects?

I am studying a system subject to random noise, or a system driven by some noise, for example, heat flow or wave propagation perturbed by noise. I would like to know if there is a real system where ...
0
votes
0answers
101 views

What's the physical interpretation of constants in Laplace equation and diffusion equation?

What's the physical interpretation of constants in wave equation and diffusion equation? $$u_{tt}=c^2u_{xx},$$ $$u_{t}=ku_{xx}.$$ Please introduce some reference about mathematical modeling of ...
1
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0answers
39 views

is log-Laplace ever an optimal model for physical phenomena?

In the financial world, the log-Laplace distribution almost perfectly models many phenomena such as price changes. Does this model best fit any physical phenomena?
0
votes
1answer
279 views

Eddy current losses in electric steel by harmonics of a magnetic field

I am working on an model of a permanent magnet synchronous machine. Right now I am stuck with calculating the eddy current losses caused by the harmonics of the stator magnetic field in the electrical ...
3
votes
4answers
1k views

Modeling incoming solar radiation

I want to write a model for estimating incoming solar radiation for a specific latitude on earth but I am struggling to find an appropriate source which shows the required equations for doing so. ...
2
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1answer
229 views

Is energy always proportional to frequency?

Google has no results found for "energy not proportional to frequency" and many results for E=hf. Is there an example of an energy that is not proportional to frequency?
6
votes
2answers
213 views

Modeling non-quantum objects (in finance, sociology etc) using fermionic fields?

Please provide (if any) applications of fermionic field theory in non-physics macro contexts (finance, sociology etc). I see only bosonic fields being used mostly. The only (minor) application of ...
1
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2answers
138 views

Does a scale model with 1/2 the linear length have 1/8 the mass?

If a scale model has 0.5x the original length in all directions, should its mass be 1/8th of the original mass?
2
votes
0answers
132 views

Turboshaft Turbine Mathematical Model

Are there any simplified mathematical models for how two gas coupled turbines (also called a free power turbine) should interact with one another as the speed of the driving turbine changes. (i.e.) ...
1
vote
1answer
68 views

If a cart hits a wall, does the weight of it affect how it moves, when the center of gravity is constant?

I have a model that represents a bicycle (a wood block with wheels), and I'm balancing the center of gravity so it's the same as a real bike. However, when the center of mass is kept constant, does ...
2
votes
0answers
67 views

Elimination of the node

Recently I have been reading a lot of astronomy papers on reductions in models of the solar system. A reoccurring concept is the elimination of the node. However, they never explain what the node is ...
1
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1answer
439 views

Definition of elementary particle [duplicate]

Possible Duplicate: Why are atoms particles? According to wikipedia an elementary particle or fundamental particle is a particle not known to have substructure. Moreover, I've learned ...
1
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0answers
55 views

Modeling the probability of a photodiode measuring photons targets at a neighbor

In current digital cameras, sensors are arrays of photodiodes which "transform" photons energy to electrons. I am aware that the probability of a photon to generate an electron is modeled by a Poisson ...
2
votes
4answers
166 views

What is the simplest system that has both, discontinous and continous phase transitions?

I am looking the simplest system that has both discontinous phase transition and a continous phase transition between the same phases (you can change one parameter). discontinous transition: first ...
4
votes
3answers
341 views

Can anyone estimate what proportion of water remains after I flush a toilet?

Imagine I have a clean toilet with some amount of water in the bowl. When I flush the toilet much of that water will be displaced by the tank's water. I want to work out (or model really) what amount ...
1
vote
1answer
349 views

Physics of the electric hot plate

For an electronics experiment, I began wondering about the electric hot-plates (specifically the temperature dependence over time). If I were to measure the given temperature over time, I assume that ...
4
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0answers
409 views

Is there any simple quantum model by Gerard 't Hooft which can explain the double slit experiment?

This question is directed to Prof. 't Hooft and anybody who is familiar with his papers. It is a reaction to Prof. 't Hooft's question why nobody is excited about his classical models for quantum ...
3
votes
2answers
114 views

A problem of approximation [duplicate]

Possible Duplicate: Why are continuum fluid mechanics accurate when constituents are discrete objects of finite size? When we apply differentiation on charge being conducted with respect to ...
3
votes
4answers
2k views

Bohr's model of an atom doesn't seem to have overcome the drawback of Rutherford's model

We, as high school students have been taught that-because Bohr's model of an atom assigns specific orbits for electrons-that it is better than Rutherford's model. But what Rutherford failed to explain ...
3
votes
4answers
322 views

Formulation of general relativity

EDIT: I think I can pinpoint my confusion a bit better. Here comes my updated question (I'm not sure what the standard way of doing things is - please let me know if I should delete the old version). ...
3
votes
2answers
288 views

Relating the power to weather variables [closed]

Could you please help me in this problem? I have 3 independent variables, (T,H,t) , as inputs and one output P ( I have all data for these inputs and the output, done experimentally measured every ...
5
votes
0answers
480 views

Interpretation of Stiffness Matrix and Mass Matrix in Finite Element Method

I would like to have a general interpretation of the coefficients of the stiffness matrix that appears in FEM. For instance if we are solving a linear elasticity problem and we modelize the relation ...
3
votes
1answer
100 views

Are there microscopic theories, which work, but which wrongly predict macroscopic behaviour?

Motivated by this question (and the P. W. Anderson article linked in that question, which I came across here somewhere today and just read) I wonder about something, which is somewhat bordering an ...
0
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0answers
80 views

References for circular restricted 3 body problem?

Does anyone know of any good references for the CR3BP -- the circular restricted 3 body problem? Emphasizing on real-life applications, and interpretation of the numerical solutions? Thank you. There ...
3
votes
1answer
413 views

The most challenging physical phenomena [closed]

What are examples of endeavors, in the history of mankind, to understand physical phenomena with models which were proved to be incorrect later, reformed significantly, or are still under ...
1
vote
0answers
193 views

Modeling the trajectory of a particle in an Electric field [closed]

[This problem has been resolved, sorry for posting in the wrong forum!] (I was trying to model the trajectory of a particle in an electric field.)
4
votes
1answer
160 views

Event-by-Event Simulation of Quantum Phenomena

I just recently stumbled over http://rugth30.phys.rug.nl/dlm/ and http://www.sbfisica.org.br/bjp/files/v38_26.pdf As the title suggests these are presentations of mathematical models capable of ...
3
votes
0answers
216 views

Simple model of the solar system. Parameters? Accuracy?

I was thinking of making a simple 2D model of the solar system, with planets moving along ellipses like $$x(t) = k_x \sin(t + k_t) (\sin(k_\phi) + \cos(k_\phi))$$ $$y(t) = k_y \cos(t + k_t) ...
3
votes
2answers
542 views

Why are continuum fluid mechanics accurate when constituents are discrete objects of finite size?

Suppose we view fluids classically, i.e., as a collection of molecules (with some finite size) interacting via e&m and gravitational forces. Presumably we model fluids as continuous objects that ...
0
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0answers
100 views

Book for learning about constructing correct physical modeling [duplicate]

Possible Duplicate: List of good classical physics books I know physics. At least I thought so until I tried to make a model of the system of scales by myself. It was confusing. For example ...
4
votes
3answers
299 views

Guessing what a simple partial differential equation is describing physically

Is there an easy way to look at a partial different equation and get a sense of what kind of phenomena it is physically describing? I have an equation that looks like this: ...