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World's Simplest Electric Train

dannym3141 says...

I'm going to assume that this is the Lorentz force, because it's the principle that involves magnetic and electric fields. But there are setups that can use subtleties of magnetic and electric fields, it can be very complicated. Any physicist rather than astronomer might be able to explain this better... or spot subtleties.

If you notice, it only starts moving once the back magnet has touched the wire. Which i think means that the wire is used to carry the current from the battery, with the magnets providing the magnetic field for the Lorentz force to drive the train. Effectively the force is felt by the electrons travelling in the wire (F = q(E + v x B), x being vector product, cross product), but there is an equal and opposite force to be felt by the 'train'; so it travels along. If you watch, it does look like the wire is responding - i'm pretty sure the small track would have shot off to the right if he hadn't held it, and it moves as the train approaches in the longer track.

So, circuit is set up by the the wire contacting between battery terminals, current flows in a circular fashion (mostly, assuming adjacent loops don't short). Magnetic field will emanate out from the battery on average radially, i assume (this is a simplification but a reasonably safe one), so the resulting cross product - and therefore direction of the force - acts along the remaining perpendicular direction to those, ie. straight up or down the loop depending on which terminal is leading.

If you want to see how that works, you can use the right hand rule. First finger is the direction of the electron's velocity (which is traversing loops so constantly changing in a circular manner), middle finger the direction of magnetic field which always comes out radially from the middle of the coil or track, thumb F the resultant force always points along the loop - make your first finger point in all directions of a circle, keep your middle finger pointing radially out relative to your first finger, and you will notice your thumb always points the same way, no matter how v changes circularly.

It is reasonable to assume that other factors are involved, probably a current is induced into the coil as the battery moves - the battery carries a magnetic field cos of the magnets, so we then have a moving/changing magnetic field in the presence of a wire; it should induce a current which would create a magnetic field in opposition to the field of the magnets.. and so on. But i think the Lorentz force is what provides most of the motion.

Bucky Ball Motor

Electric Motor Made out of Buckyballs

siftbot says...

Tags for this video have been changed from 'Buckyballs, magnets, electricity, Lorentz' to 'Buckyballs, magnets, electricity, Lorentz, Buckminsterfullerene, c60, motor' - edited by BoneRemake

Seeing the World at the Speed of Light

kceaton1 says...

>> ^GeeSussFreeK:

>> ^garmachi:
It's been many years since I studied physics. What does the lowercase gamma in the bottom left represent?


Me to, I think the answer is in here, but eff if I can remember.
Edit: ok I think it is the "Lorentz factor" . 7.089 Lorentz factor is 0.990 ratio to the speed of light (or very very close)


Lorentz sounds like it to me too. There are only a few other choices it could be, but I don't see them really relating very well to the what's in the video (gamma brightness for the "video", or gamma radiation factor from nuclear sciences--both I highly doubt).

Lorentz transformations (which is linked above by @GeeSussFreeK ) would be the way you would calculate many of the dilation effects caused by relativistic effects traveling near the speed of light.

Traveling at the speed of light you would have a pinpoint in front and in back. The light up front, the size of a point and basically nothing behind, as it would be shifted to very low levels of radiation. If you're going at the speed of light you wouldn't be doing any calculations as time has stopped, but from your vantage point everything happens at the same speed. As you slow down though far from the speed of light, in less than a second you instantly see things change all around you depending on how long of course you had been going at the speed of light (if you had been going that speed for 10 years you won't see too much; but, what about one billion years--can you imagine...).

But, to you a second was still one second even at that speed, or any speed, even as time slowed down the closer you got to the speed of light. Everyone else will of course still count their seconds the same as well. Hence, relativity.

If you did go that fast, yet had mass you would be facing some HUGE problems. At the front you would find a tremendous amount of energy (I'd guess all of it would be shifted to the highest energy level; one huge one-dimensional jet of gamma radiation) and at infinite amounts. In other words, it's impossible to do it. that is why a lot of Sci-Fi uses space warping/tearing/etc... to connect yourself to another place, like a wormhole; or bend space in front and back of you like Star Trek and use warp.

Gotta love Einstein and his little revelation--and all revelations in science or otherwise that add to the understanding, the expanses created, broadening our horizons, windows to the wondrous mountains of the mind put into view, and all of reality's grandeurs still there to be conquered and our dreams explored. It makes this world just a bit more interesting and worth bothering to get up every morning and go about our daily routines.

/corny

Seeing the World at the Speed of Light

juliovega914 (Member Profile)

Ornthoron says...

But massive particles would still be prohibited from traveling faster than the speed of light. It's only the particles with imaginary mass that could travel faster, and they would still fit into the framework of special and general relativity.

Unless we at the same time can show that the neutrinos have non-complex mass. Then it could get really hairy. But I wouldn't bet my house on it.

In reply to this comment by juliovega914:
An exaggeration, yes, but not a terribly big one. Most of the standard theory today is based on the bricks of special and general relativity. For us to have to rethink the laws restricting mass from traveling over the speed of light, we really would need to rethink physics from there all the way back up, which really leaves no physical theories safe all the way back to Newtonian physics. In short, I cant wait to see how this pans out.

In reply to this comment by Ornthoron:
Oh, it would definitely be groundbreaking. One of the biggest discoveries in physics to date. But to say that we would have to restart physics is an exaggeration.

In reply to this comment by juliovega914:
I'm pretty sure negative mass would still result in complex energy, because the Lorentz transformation factor would still be proportional to 1/i or -i. Complex mass, however, would allow for the energy to be real (which has been theorized as being possible), but that introduces a whole new problem of trying to conceptualize complex mass.

And on a side note, the first ever physical observation of nonpostive/nonreal mass would be groundbreaking in its own right.

In reply to this comment by Ornthoron:
The thing is, we don't know the mass of the neutrino. If it has a tachyonic nature, i.e. negative mass squared, it could break Lorentz symmetry while still satisfying Einstein's equations.

>> ^juliovega914:

>> ^Jinx:
>> ^juliovega914:
If this measurement turns out to be true, we basically have to restart physics.

Again, not necessarily. It would be a ground breaking discovery and would certainly raise a lot of questions...but then I did perhaps one of the most brain melting experiments with results that appear to contradict theory and common sense when I was 14 years old. http://en.wikipedia.org/wiki/Double-slit_experiment

No, it would be a HUGE discovery! One of the biggest ever! and it would completely redefine our modern theory!
If a massive particle moves faster than the speed of light, that means the Lorentz factor for calculating the energy of the particle will be complex! (gamma = c/squrt(c^2-v^2), for v>c, gamma is complex). Do any of you have any fucking idea what that means?
(http://hyperphysics.phy-astr.gsu.edu/hbase/relativ/veltran.html
for those of you who dont know wtf I am talking about)





Ornthoron (Member Profile)

juliovega914 says...

An exaggeration, yes, but not a terribly big one. Most of the standard theory today is based on the bricks of special and general relativity. For us to have to rethink the laws restricting mass from traveling over the speed of light, we really would need to rethink physics from there all the way back up, which really leaves no physical theories safe all the way back to Newtonian physics. In short, I cant wait to see how this pans out.

In reply to this comment by Ornthoron:
Oh, it would definitely be groundbreaking. One of the biggest discoveries in physics to date. But to say that we would have to restart physics is an exaggeration.

In reply to this comment by juliovega914:
I'm pretty sure negative mass would still result in complex energy, because the Lorentz transformation factor would still be proportional to 1/i or -i. Complex mass, however, would allow for the energy to be real (which has been theorized as being possible), but that introduces a whole new problem of trying to conceptualize complex mass.

And on a side note, the first ever physical observation of nonpostive/nonreal mass would be groundbreaking in its own right.

In reply to this comment by Ornthoron:
The thing is, we don't know the mass of the neutrino. If it has a tachyonic nature, i.e. negative mass squared, it could break Lorentz symmetry while still satisfying Einstein's equations.

>> ^juliovega914:

>> ^Jinx:
>> ^juliovega914:
If this measurement turns out to be true, we basically have to restart physics.

Again, not necessarily. It would be a ground breaking discovery and would certainly raise a lot of questions...but then I did perhaps one of the most brain melting experiments with results that appear to contradict theory and common sense when I was 14 years old. http://en.wikipedia.org/wiki/Double-slit_experiment

No, it would be a HUGE discovery! One of the biggest ever! and it would completely redefine our modern theory!
If a massive particle moves faster than the speed of light, that means the Lorentz factor for calculating the energy of the particle will be complex! (gamma = c/squrt(c^2-v^2), for v>c, gamma is complex). Do any of you have any fucking idea what that means?
(http://hyperphysics.phy-astr.gsu.edu/hbase/relativ/veltran.html for those of you who dont know wtf I am talking about)




juliovega914 (Member Profile)

Ornthoron says...

Oh, it would definitely be groundbreaking. One of the biggest discoveries in physics to date. But to say that we would have to restart physics is an exaggeration.

In reply to this comment by juliovega914:
I'm pretty sure negative mass would still result in complex energy, because the Lorentz transformation factor would still be proportional to 1/i or -i. Complex mass, however, would allow for the energy to be real (which has been theorized as being possible), but that introduces a whole new problem of trying to conceptualize complex mass.

And on a side note, the first ever physical observation of nonpostive/nonreal mass would be groundbreaking in its own right.

In reply to this comment by Ornthoron:
The thing is, we don't know the mass of the neutrino. If it has a tachyonic nature, i.e. negative mass squared, it could break Lorentz symmetry while still satisfying Einstein's equations.

>> ^juliovega914:

>> ^Jinx:
>> ^juliovega914:
If this measurement turns out to be true, we basically have to restart physics.

Again, not necessarily. It would be a ground breaking discovery and would certainly raise a lot of questions...but then I did perhaps one of the most brain melting experiments with results that appear to contradict theory and common sense when I was 14 years old. http://en.wikipedia.org/wiki/Double-slit_experiment

No, it would be a HUGE discovery! One of the biggest ever! and it would completely redefine our modern theory!
If a massive particle moves faster than the speed of light, that means the Lorentz factor for calculating the energy of the particle will be complex! (gamma = c/squrt(c^2-v^2), for v>c, gamma is complex). Do any of you have any fucking idea what that means?
(http://hyperphysics.phy-astr.gsu.edu/hbase/relativ/veltran.html for those of you who dont know wtf I am talking about)



CERN scientists break the speed of light with neutrinos

juliovega914 says...

>> ^Ornthoron:

The thing is, we don't know the mass of the neutrino. If it has a tachyonic nature, i.e. negative mass squared, it could break Lorentz symmetry while still satisfying Einstein's equations.
>> ^juliovega914:
>> ^Jinx:
>> ^juliovega914:
If this measurement turns out to be true, we basically have to restart physics.

Again, not necessarily. It would be a ground breaking discovery and would certainly raise a lot of questions...but then I did perhaps one of the most brain melting experiments with results that appear to contradict theory and common sense when I was 14 years old. http://en.wikipedia.org/wiki/Double-slit_experiment

No, it would be a HUGE discovery! One of the biggest ever! and it would completely redefine our modern theory!
If a massive particle moves faster than the speed of light, that means the Lorentz factor for calculating the energy of the particle will be complex! (gamma = c/squrt(c^2-v^2), for v>c, gamma is complex). Do any of you have any fucking idea what that means?
(http://hyperphysics.phy-astr.gsu.edu/hbase/relativ/veltran.html for those of you who dont know wtf I am talking about)



I'm pretty sure negative mass would still result in complex energy, because the Lorentz transformation factor would still be proportional to 1/i or -i. Complex mass, however, would allow for the energy to be real (which has been theorized as being possible), but that introduces a whole new problem of trying to conceptualize complex mass.

And on a side note, the first ever physical observation of nonpostive/nonreal mass would be groundbreaking in its own right.

Ornthoron (Member Profile)

juliovega914 says...

I'm pretty sure negative mass would still result in complex energy, because the Lorentz transformation factor would still be proportional to 1/i or -i. Complex mass, however, would allow for the energy to be real (which has been theorized as being possible), but that introduces a whole new problem of trying to conceptualize complex mass.

And on a side note, the first ever physical observation of nonpostive/nonreal mass would be groundbreaking in its own right.

In reply to this comment by Ornthoron:
The thing is, we don't know the mass of the neutrino. If it has a tachyonic nature, i.e. negative mass squared, it could break Lorentz symmetry while still satisfying Einstein's equations.

>> ^juliovega914:

>> ^Jinx:
>> ^juliovega914:
If this measurement turns out to be true, we basically have to restart physics.

Again, not necessarily. It would be a ground breaking discovery and would certainly raise a lot of questions...but then I did perhaps one of the most brain melting experiments with results that appear to contradict theory and common sense when I was 14 years old. http://en.wikipedia.org/wiki/Double-slit_experiment

No, it would be a HUGE discovery! One of the biggest ever! and it would completely redefine our modern theory!
If a massive particle moves faster than the speed of light, that means the Lorentz factor for calculating the energy of the particle will be complex! (gamma = c/squrt(c^2-v^2), for v>c, gamma is complex). Do any of you have any fucking idea what that means?
(http://hyperphysics.phy-astr.gsu.edu/hbase/relativ/veltran.html for those of you who dont know wtf I am talking about)


CERN scientists break the speed of light with neutrinos

Ornthoron says...

The thing is, we don't know the mass of the neutrino. If it has a tachyonic nature, i.e. negative mass squared, it could break Lorentz symmetry while still satisfying Einstein's equations.

>> ^juliovega914:

>> ^Jinx:
>> ^juliovega914:
If this measurement turns out to be true, we basically have to restart physics.

Again, not necessarily. It would be a ground breaking discovery and would certainly raise a lot of questions...but then I did perhaps one of the most brain melting experiments with results that appear to contradict theory and common sense when I was 14 years old. http://en.wikipedia.org/wiki/Double-slit_experiment

No, it would be a HUGE discovery! One of the biggest ever! and it would completely redefine our modern theory!
If a massive particle moves faster than the speed of light, that means the Lorentz factor for calculating the energy of the particle will be complex! (gamma = c/squrt(c^2-v^2), for v>c, gamma is complex). Do any of you have any fucking idea what that means?
(http://hyperphysics.phy-astr.gsu.edu/hbase/relativ/veltran.html for those of you who dont know wtf I am talking about)

CERN scientists break the speed of light with neutrinos

juliovega914 says...

>> ^Jinx:

>> ^juliovega914:
If this measurement turns out to be true, we basically have to restart physics.

Again, not necessarily. It would be a ground breaking discovery and would certainly raise a lot of questions...but then I did perhaps one of the most brain melting experiments with results that appear to contradict theory and common sense when I was 14 years old. http://en.wikipedia.org/wiki/Double-slit_experiment


No, it would be a HUGE discovery! One of the biggest ever! and it would completely redefine our modern theory!

If a massive particle moves faster than the speed of light, that means the Lorentz factor for calculating the energy of the particle will be complex! (gamma = c/squrt(c^2-v^2), for v>c, gamma is complex). Do any of you have any fucking idea what that means?

(http://hyperphysics.phy-astr.gsu.edu/hbase/relativ/veltran.html for those of you who dont know wtf I am talking about)

CERN scientists break the speed of light with neutrinos

Ornthoron says...

>> ^Enzoblue:

>> ^Ornthoron:
A little cold water for everyone:
If these results turn out to be solid, it will not necessarily conflict with Einstein's theory of relativity. Relativity can accomodate these particles if they have negative mass.

Negative mass doesn't even make sense to me. You either have mass or you don't. You can't really really really not have mass all you want, but it doesn't make you negative. Please explain.


Sorry, I miswrote. I meant to say imaginary mass, just like tachyons. It's the mass squared that is negative.

To a physicist, mass is just a number describing a certain property of particles, namely their inertia and gravitational attraction. To date, all observed particles either have real positive mass or are massless, but that does not mean that some other value (negative or even complex) is theoretically impossible. The Standard Model of particle physics is far from complete, and there are extensions to it that include Lorentz symmetry breaking and thus can accomodate faster than light neutrinos.

E=mc² is wrong?

ajkido says...

>> ^harry:
One question they didn't really answer in this bit: why is the factor the speed of light squared? Besides it being a result of the maths, what does that relationship actually mean?


I think it comes from the Lorentz factor y = 1 / sqrt(1 - v^2 / c^2)

And why the speed of light is in the Lorentz factor is another story. I guess Feynman was spot on in that magnet video...

Leonard Susskind on String Theory

botelho says...

Let us put in a correct perspective quantum string theory for TOE. Firstly it is important to remark that a full understanding of what is really Quantum Mechanics is far to be completely understood in its foundational aspects ,althougth its huge operational-quantitative success.For instance, even in the usual non relativistic quantum mechanics , certainly the notion of electronic orbitals in N-electron atomic physics appears to be a mathematical suitable approximation for the full N-electron atomic wave function.On the other hand in Quantum Field Theory , this ad-hoc choice of what is free and what is interaction is not so "ad-hoc", at least in the QFT (perturbative) scattering sector: free in and out fields are primary objects producing physically observables free N-particles (lorentz invariant!) wave functions-so perturbation is building around them and carrying with the formalism all notions of renormalizations , dispersions relations etc.. .Now quantum strings : Strings are supossedly observable for us mainly through scattering among its excitations by means of an already fixed sigma-model two-dimensional quantum dynamics taking place in the somewhat ficticious purely two dimensional string parameter space-time, where are operating two scales of interaction : one is entirely ruled by the intrinsic string topological genera and other governed by the extrinsic space-time coupling constant , namely : The Regge Slope parameter. So string theory for TOE is a proposal for pure S-Matrix "Heisenbergnian" on-shell "theory" for all particles scattering in Nature (including gravitons). Now the theory's "granus salis" (points not completely grasped-at least for this reader !): Back ground fields are fixed extrinsic classical field configurations fully determined by the imposition of conformal invariance for any genera (which certainly does not affects the intrinsic 2d UV-theories'behavior,but affects its IR intrinsic behavior as a 2d QFT) and at any order in the Regge Slope coupling (all these conformal invariance phenomena quite specific to Polyakov's action proposal , possibly not for a Nambu-Goto string action reformulation of TOE).And at the same time , they are expected to be Schwinger sources (even quite non linear) for the string excitations and to be functionally differentiated in the string path-integral later .Another point is related to Kaluza-Klein Theories -It appears that quantum geometrical theories appear to be trivial QFT theories when used to describe scattering in space-time extrinsic manifolds of higher dimensionality (lambda four scalar QFT is expected to be trivial for D strictly greater than four!). As a conclusion : at most Strings are useful theoretical labs for a fully understanding of what really is Quantum Mechanics (SchrodingerX HeisenbergXEinsteinXNelson) , if there are no experimental tests for its predictions .By the way,space-time supersymmetry still remains solely as a theoretical lab in Particle Physics, nothing more!.

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