Recent content by jrosen13
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J
Undergrad Motion of a photoelectron
One step model is way better :)- jrosen13
- Post #12
- Forum: Quantum Physics
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Graduate Gravitationally amplified quantum fluctuations
The idea here seems to be that the very large energy density in the gravitational field would result in relatively large quantum fluctuations in mass density, and that perhaps these fluctuations in mass could effect some astrophysical phenomenon such as a star on the verge of supernova. The...- jrosen13
- Post #2
- Forum: Quantum Physics
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Graduate Eigenvalues and eigenvectors of a 3x3 matrix (principal stresses)[programming]
That was my feeling before, that numerically you can solve a cubic polynomial to whatever accuracy you desire, up to some fundamental limit of time cost perhaps, but that you should be able to get really close without too much trouble. However, it is possible to analytically solve it! e.g...- jrosen13
- Post #9
- Forum: Linear and Abstract Algebra
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Solving One Dimensional Wave Motion with Mass m
I just noticed you wrote your spring constant as a function of x, but that wouldn't be right, would it?- jrosen13
- Post #7
- Forum: Advanced Physics Homework Help
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Undergrad Is heat's velocity constant like light's?
I would say that is a very crude model that doesn't explain many of the properties of conduction, for instance why does the rate of heat flow between two objects in contact depend on the pressure applied on the contact surface (and it definitely does). Why does a fairly good conductor transfer...- jrosen13
- Post #30
- Forum: Thermodynamics
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J
Undergrad Is heat's velocity constant like light's?
Conduction is not a microscopic idea, but a macroscopic one. These ideas were developed well before quantum mechanics ever existed, by observing large objects in contact with each other, or not in direct contact that still transfer heat. This was understood as radiation, which was an...- jrosen13
- Post #28
- Forum: Thermodynamics
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J
Graduate Eigenvalues and eigenvectors of a 3x3 matrix (principal stresses)[programming]
Mathematica would just give you the answer, Eigenvalues[matrix], done. To calculate yourself, sure get your cubic polynomial and figure out a way to solve it, numerically perhaps?- jrosen13
- Post #4
- Forum: Linear and Abstract Algebra
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J
Graduate How to Approach Solving a 2D Damped Wave Equation?
separation of variables to turn it into ordinary differential equations. It looks like __ equation for spatial part, and __ for time part, but I won't fill in the blanks, that's cheating :)- jrosen13
- Post #2
- Forum: Differential Equations
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Solving One Dimensional Wave Motion with Mass m
It wasn't so bad was it? That looks right to me, harmonic oscillator all the way. In the future try to realize if you are patient and think it through a little you will figure it out. Don't be in a hurry to get the answer, enjoy the process of figuring it out for yourself!- jrosen13
- Post #6
- Forum: Advanced Physics Homework Help
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Solving One Dimensional Wave Motion with Mass m
Sorry that was basically overkill, I had different idea in mind when i looked at it quickly before. Sketch the potential, where does the mass start out? Is it reasonable to approximate the potential by one that you know well?- jrosen13
- Post #4
- Forum: Advanced Physics Homework Help
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Fraction of Radiation Detected
Yep, you assume 100% detection efficiency in the detector (since you detect 50% right next to the source this is implied), which is basically never going to happen in real life due to charge leakage or readout noise and many other effects.- jrosen13
- Post #14
- Forum: Introductory Physics Homework Help
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Solving One Dimensional Wave Motion with Mass m
Looks like an instanton to me. Anyways, don't you just do the normal lagrangian/hamiltonian methods here? Its just a classical problem, right?- jrosen13
- Post #2
- Forum: Advanced Physics Homework Help
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Graduate Feynman Path Integral's Meaning
In physics, when one has a crazy idea that works, it may be necessary to state that it is not the only way to look at it so people don't simply dismiss it because it seems crazy. The essence is that the classical path is a stationary point of the action, i.e. a maximum/minimum/ or saddle point...- jrosen13
- Post #8
- Forum: Quantum Physics
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Fraction of Radiation Detected
This is correct except you divided by two at the end. The question asks what fraction of the total radiation you detect. To do this absolutely correctly you are just talking about the solid angle that detector covers with the point source at the origin. At first it covers 2pi solid angle, so...- jrosen13
- Post #12
- Forum: Introductory Physics Homework Help
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Undergrad Is heat's velocity constant like light's?
I think that in this forum there is really only so much you can say before it is like writing a book on the subject. Here we can only answer specific questions, but at some point people will need to open a standard textbook on the subject and get the hard facts. If there is still questions...- jrosen13
- Post #26
- Forum: Thermodynamics