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| bio | website | inspirehep.net/… |
|---|---|---|
| location | Duchy of Grand Fenwick | |
| age | 42 | |
| visits | member for | 2 years, 6 months |
| seen | 6 mins ago | |
| stats | profile views | 3,183 |
Experimental particle physicist. These days I'm doing neutrinos.
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4m |
answered | Where does the extra equation come from to determine the forces from an object on a table? |
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26m |
comment |
$1/r^5$ multipole potential with point particles? Ah, I see. The arrangement into point, line, square cube is not necessary. The arrangement of three charges -q at (-d,0) ,+2q at (0,0) and -q at (d,0) is also a pure quadrupole, and there are others. Look for a formal definition of what makes a n-pole. |
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36m |
comment |
$1/r^5$ multipole potential with point particles? Surely you've noticed a pattern in the four cases you quote. Maybe you can deduce the next step in the sequence. (Might be best to not worry about the word you would use, and just concentrated on the arrangement.) |
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21h |
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Terminal velocity of all falling objects is same? Ah, a chance to get all sciency. Drop a feather and a tennis ball side by side and draw your own conclusion. |
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22h |
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Can a linear momentum generate angular momentum at collision? It is also worth noting that if you look only at one part of a system you can give it some new angular momentum $L$ by doing some work (but you are ignoring the $-L$ that you have imparted to the other part of the system). |
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22h |
comment |
Can a linear momentum generate angular momentum at collision? You can look at this on several levels. At the lowest level there was a pre-existing angular momentum between the hand and the ball and some is transferred. At the next level out you had to push on the ground to move the hand and that does modify the Earth's angular momentum at some level. But not necessarily "sapped" it depends what direction the pushes are in. The guarantee it that $L_{\mathrm{Earth},i} + L_{\mathrm{you},i}+ L_{\mathrm{ball},i} = L_{\mathrm{Earth},f} + L_{\mathrm{you},f}+ L_{\mathrm{ball},f}$ (all measurements around some inertial center). |
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22h |
comment |
Electric dipole moment, which charge is the $q$ for? You book no doubt sets this up with a particular situation. Look back at how they defined it... |
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22h |
answered | Can a linear momentum generate angular momentum at collision? |
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1d |
comment |
How long would it typically take to develope nuclear weapons these days? Related (but also closed) question where you will find some relevant comments: physics.stackexchange.com/questions/38626/… and physics.stackexchange.com/questions/31047/…. |
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1d |
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Collision between a photon and an electron "I could claim that the diffraction pattern observed in the double-slit experiment is due to compton scattering, among other factors." The cross-section for Compton scattering can be measured and is a simple function of angle that does not correspond to diffraction patterns. I know that pop-sci books make it seem reasonable to think about physics in terms of word pictures, but you must learn the math. |
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1d |
comment |
Increasing Amps I'm treating this as a practical questions---from a physics point of view the answer is that you simply need a higher current supply or to ration your power consumption, but you already figured that out. |
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1d |
comment |
Can one define a “particle” as space-localized object in quantum field theory? @Neuneck Er...yeah. Sorry. |
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1d |
reviewed | Approve suggested edit on Magnetic Field on a particle between two Helmholtz Coils |
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1d |
comment |
Can one define a “particle” as space-localized object in quantum field theory? If the wave packet is to have finite width in both position and momentum then the kernel of the integral has to be a finite peak rather than a delta function. |
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1d |
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Collision between a photon and an electron I can't speak to the downvote, but adding a link to a n-page pdf and expecting you reader to page through it is not making things easy for someone you are asking to help you. The question appears to concern itself with the backwards limit of Compton scattering. |
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1d |
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Can one define a “particle” as space-localized object in quantum field theory? This derivation is effectively done in the momentum basis---which is just a valid and correct as the position basis---but because these excitations have well defined momentum Heisenberg tells us that viewed in that basis they do not have well defined position. To get the thing that you are used to you need to pick a basis in which both position and momentum are roughly localized; that's the wave-packed formalism that Trimok talks about, but it is mathematically difficult and we mostly calculate in momentum space. |
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1d |
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Calculate the distance between two points from iPhone Camera Without a stereoscopic view you must either know the distance to the target or find a calibration from pixes/second to linear-distance/second. I am, however, wondering if light field cameras can drag the range out of the data. Wouldn't that be spiffy? |
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1d |
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How can the big bang occur mathematically? See physics.stackexchange.com/q/7838 and physics.stackexchange.com/q/2355. |
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1d |
reviewed | Approve suggested edit on Are Colors Emitted at Specific Temperatures? |
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1d |
comment |
The Sine pattern of variation This simply reflects what kinds of problems you've studied to date. |
