CasualKilla

Agreed. But perhaps you would like to elaborate on your answer. I agree than twin B experiences acceleration, but in this paradox we only consider special relativity. In that case, ok the velocity goes negetive, fine, I agree, but I do not see how to extrapolate that to solve the paradox.

I gave you negative feedback because I out of 4 posts, not a single one added any value and you were getting rude and personal. I stand by it. I do not see where is special relative the sign makes any difference in the calculations. I am open to that idea, please just show me your logic.

Does this help? Atleast it shows the observers on the train disagree with the blokes outside about simultaneity of events. NEW POST! I have being doing some 2D special relativity calculations, and I have come up with some conclusions that may help. I assume a train speed of 0.87c, and I will have the clocks emit a pulses at 2hz, and due to the length of the train, the middle clock will also pulse also at 2hz, but with a slight delay. (with reference to on train observer) Conclusions from calculations: All clocks experience the same time dilation, and the observer outside the train will see each clock pulsing at 1Hz. (v = 0.87c) The outside observer does not see the front and back clocks flash at the same time, though the flash RATES are observed to be the same. Order of observations (long train):Front clock is observed to flash first. Back clock flashes second. Middle clock flashes last. However I noticed something very interesting, if the distance between side and middle clocks is small, the time delay as observed by the observer on the train will also be small. If this delay is small enough, the observer outside the train will actually observe the middle clock flash before the back clock. So this changes the order of observation for a short train: Order of observations(short train): Front clock is observed to flash first. Middle clock flashes second Back clock flashes last What a truly amazing result. This was a misunderstanding of the maths, since the middle clock is signalled by the front and back clocks with light, I can't just make the delay as short as i want, the delay is directly fixed to the length of the train, but as the length decrease, the time delay between Cb and Cf also decreases, the result in that the middle clock always flashes last. The part at the end of the video about space-time separation should explain this a bit better. This leads to an interesting new conclusion: assumption: 2 systems at rest within the same reference frame separated by a finite distance L cannot cause an affect on one another faster than t = L/c. If event A causes event B, then event A occurs before or simultaneously with event B in any reference frame. I believe the rest of my calcs were sound, I used the theory in this lecture as reference. https://www.youtube.com/watch?v=mG-rO9KLpHc

I similarly have my doubts, based on simple intuition, but sometimes we must put that aside. This is not a question of belief, I am reading the material and trying to make sense of it. I understand you are just trying to help, and I appreciate that, but from here it looks like you are the one clinging to beliefs... I have PMed you an extract of the handbook, perhaps the Maths makes sense to you.

You seem quite happy with the explanation that "one twin is different", but you can't seem to articulate why that makes a difference (within special relativity). Relative velocities remain the same at all points. If I did not want to learn, I would not have posted this thread in the first place, that is a rather stupid claim. Is doppler shift of light caused by time dilation, length contraction, or both?

Do you think it is legit though? The doppler explanation seems to work even if the twins experience no time dilation, it is simply the light changing frequency, and then uses the finite speed of light to explain why beeps are different.

Firstly, great response, thank you very much. I will be re-reading several times. Just another comment on the observation though, when using special relativity, we assign relative speeds, distances etc. and then we can get the relative times and distances for each reference object. Does this assume perfect information of objects, even though the objects may be lightyears apart, therefore there can be no way to determine the actual values of both objects in the same instant. Then results are obtained, but these are not the observed results, we need to wait a couple lightyears to check if our prediction were right? Are we measuring the effect on incoming light from objects, or the objects themselves? Was not talking about the siren example, I was just trying to show why I found the doppler effect explanation of the paradox silly. I admit my logic was flawed on the siren example, but that is not my question. I regret posting that siren example, I knew it was not correct, but I was thinking that perhaps it was incorrect for the same reason the doppler shift twin paradox explanation was incorrect.

One experiences acceleration, sure, but what if there was a worm hole that allowed him to change direction instantly, lets remove that variable completely.

That is interesting since then observation would just mean detecting the photons, how do we know objects actually change length, perhaps it is just how we perceive the photons? For example, fly near the speed of light, then you see stars changing shape, but for all we know that star may already be dead, we are just changing how we observe the photons.. Yes, but that is general relativity. Do you need to go there to solve the paradox?

I did, they both experience the same time dilatation, since the relative motion is same for both. If it could be so simply solved it wouldn't be a paradox would it...

I have been thinking about a way to explain the twin paradox, I came across a video where both twins have synchronized clocks that emit a light pulse every 1 minute. When they are moving apart, both the earth twin and the spaceship twin experience doppler shifted pulse of 2 minutes.(v = 0.87c). Then when the spaceship twin turns around, he experiences doppler shifted pulse from the earth every 30 seconds. The earth however, still receives the the 2 minute pulses until the information that spaceship twin has turned around reaches them (depends of distance), after which earth also receives 2 minute pulses. When the twins gets back together, both agree that earth twin sent more pulses. Thus space twin is indeed younger. Now I do not find this a satisfactory explanation, since the same argument can be made for say a fast car with a 1hz siren and a stationary observer with another 1Hz siren. We know for certain at these low speeds there will be almost negligible time dilation, but the car will measure more beeps from the stationary object, since it will also take a while for the sound information to travel back to the observer to tell him he has turned around. Is this argument fallacious, or am I getting something wrong? I think I see the problem with this explanation, since it does not address the fact that both twins experience the same time dilatation relative to the other, ie they both observe the other going at 1/2 speed. Then pulls a bait and switch by showing you that one twin received less pulses than he sends out, making you assume that their times where different without even using relativity in the first place. Another thing, this explanation seems to use the fact that light is the tool used for observation. Is this what Einstein intended, or can an observer observe things "instantly" without relying on the delay cause by the finite speed of light?

Oh ok I see what you mean by smoother operation now, if flux carrier = flux teeth you could have the flux being completely blocked at a certain orientation. Uneven numbers allow flux to enter the rotor into the flux carriers at any orientation. I believe this is *similar to the reason we apply a slight slant to induction motors, otherwise you have large torque when aligned with the stator teeth and smaller torque when no aligned. Similarly, you don't want conductor bars = stator teeth. One thing I must mention is that a rotor design like (above) has a mathematical limit of 3 for the saliency ratio (can't find the proof on the web, but it is in HANDBOOK OF ELECTRIC MOTORS Second Edition, Revised and Expanded), whereas a design with separated flux carriers can achieve much higher saliency ratios (more than 10) The torque and PF in these machines dependent on the saliency ratio. Derivation of these equations involve implementing the dq axis transformation. http://en.wikipedia.org/wiki/Dqo_transformation#Geometric_Interpretation Which coverts the stator winding into 2 dc (WHATTT??) currents. The Ld and Lq is defined and the salency ratio = Ld/Lq. So, the multi-carrier design can achieve a much higher torque, the smooth operation is just a nice bonus. Trouble is I cant intuitively figure how the multi-carrier design achieves better saliency, and the maths is beyond me.

I was thinking about a zero g environment, where the spinning tail would be the simplest solution. Look at the cats trying to figure it out here, silly cats.

It is very easy to rotate with no eternal forces, specially for beings with tails (such as cats or super sayans) simply rotate your tail and there you go, then stop rotating it when u have reached your desired angle. Not complex at all, cats try all kinds of things in space, but I don't think they realize that only their tails are making a difference, silly cats.

Thank you for your input enthalpy, I really appreciate you taking the time to give a well thought out answer. I just have to query one thing you said though, "same properties and performances of any reluctance motor". This design differs from a switched reluctance machine quite heavily, since the stator configuration is very different. This machine uses the same stator as the induction machine. Why do you think separated flux carriers are used, instead of one large cross like a switch reluctance machine, is the the due fact that flux is delivered from discrete stater teeth, rather than the perfectly uniform rotating field we like to imagine the stator creates.

Well they the same magnitude angular momentum with reference to the same point. You need to use parallel axis theorem on the wheel or the earth, or both if you don't choose one of their centers as the reference (not recommended). But ok you are right, I didn't realize I said angular momentum instead of velocity, my mistake.

Yes I believe so, otherwise where is the this second counter rotating wheel you speak of? If we span 2 wheels in different direction then what you say is true, i though it would be more interesting to consider one wheel and where the angular momentum is going. It is something I considered yesterday and when it finally clicked spinning the wheel also spins the earth, it was a really interesting realization. I just wanted to share that feeling! No, the earth has much higher inertia than the wheel, it will have a very small change in angular velocity. Do the calcs, you will be amazed by how small it actual is.

What is a wire carry the the same AC current is the opposite direction why placed next to it. Lets assume very very thin wires.

Ok, but it is still possible to apply a field that mimics that created by a current exactly, which would not induce a current, but I see your point now, it is still useful and possible to use the law in reverse, I was just a bit butthurt that it didn't work like I originally thought. I have an intersting question, is I have an varying current that produces B(r,t) outside the wire, then I apply an external field around the wire that produces exactly -B(r,t), what will be the current in the wire ie. 0, constant, AC current etc. Facepalm, I already said I have a current a producing B(r,t) so, but the -B(r,t) will produce an EMF right? how does that effect the system?

That is probably due to the initial uneven distribution of iron filings. Also imbalance will be compounded since the iron filing become magnetized adding their own magnetic dipole moments at the poles, thus creating a stronger field in that vicinity. Think of it as adding tiny little magnets to each side, the side with more magnets will naturally have stronger attractive ability and compete more strongly remaining iron filings. #monopoly#survivalofthefittest#darwinwasright

My thread, my question. Whether you choose to give value to my marks is up to you.

No, the magnetic field (or a portion of it) could be applied by an external magnet, you do not know for a fact that there is current in the wire.

Guys come-on really . "magnetic potential energy" = "change in potential energy between the two magnets due to their loss of mutual attraction". Does anyone disagree with that definition? If not can we move on and answer this man's question? I agree that the question is magnetized or magnetized state higher energy is interesting and important, but it is not relevant to the question posed by the OP.

Wait, what does it inforce when the pulse is high, also 0 volts??

Mass to light is baby science, light to mass though, definitely possible in theory, but that would be truly amazing. May have serious applications in "propellant-less" thrust for space travel. What mass would be created?? Please link !!