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tvp45

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Posts posted by tvp45

  1. Yes, I throw my vote in with ewmon and davey2222. The effect can be readily seen by using a helium birthday balloon, which "rises" in the direction of acceleration in the same fashion as heated air. The layer of air adjacent the windows would of course be heated.

  2. I'd recommend

     

    Les Miserables by Victor Hugo. Paints an accurate picture of the struggle between moral right and legal right.

     

    Huck Finn by Mark Twain. Shows America in the best and worst lights through the eyes of a young man.

     

    Street without Joy by Bernard Fall. Shows the ultimate failure of colonialism in a vivid manner.

     

    The Guide for the Perplexed by Moses Maimonides. A practical philosophy book that remains topical after 800 years.

  3. Voltage is the potential energy per unit charge. There is always a potential difference causing current, even when it is very tiny. Let's say you have 3.000 V at point A. This means relative to point B. The end of the resistor nearest point A might have somethin like 2.9989 V, the small difference being what it takes to make the current in the wire. Likewise, at the end of the resistor nearest point B, you might have 0.0008 V, again the small potential difference being needed to have current in the wire.

     

    We normally just ignore the small potential differences across the wires.

  4. There is no shame in ignorance. However, being stupid about your own ignorance is terrible. That people do not have the humility to say, well I really have no clue, why don't you ask someone who knows? That's what's shocking and I dare say dangerous. They don't really need to know much about science, they just need to know that they don't know, and then defer to someone who does. The same applies to every other subject.

     

    I quite agree. I've never been blessed with extraordinary intelligence or a great education. So, I've made it a point to notice who is smart and then I listen to what they say and try to remember as much as I can. I freely, and often, admit that I don't know something, and that gives me the freedom to go find out. Turns out I do have a good knack for figuring out who really does know things vs who just puts on airs.

  5. Hello,

     

    Not a strange question, but a loosely defined one. I sort of know the answer because I get to tie up the little sand bags that anchor the balloons at the annual fete at a local adoption agency.

     

    But, I think this is a class assignment? So, you must have held such a balloon at some time. Can you close your eyes and remember the pull on your hand? Would you say it was enough to lift a toothpick? How about a small coin? A pack of gum?

  6. Wow, that rhymes...

     

    Wouldn't Occam's Razor lead to the conclusion that Time itself is infinite, without a beginning or an end?

     

     

    I should think a strict application of Ockham would just be "We can measure local elapsed time heuristically." After that, it gets complicated.

  7. @ Sisyphus.

     

    Thanks, I had to read the blasted thing twice more before I saw it.:doh:

     

    I think the problem is that it is actually impossible for a "conspiracy" of some kind not to exist.

     

    Directors and Boards of companies have a legal obligation to maximise the returns to investors and can be charged for not doing so. Under these conditions it becomes imperative for any company threatened by a new technology to either gain control of it or minimise or destroy it.

     

    For example, if by some feat of genius someone actually made a car motor that ran on water, then oil company execs have a legal obligation to control or destroy the idea as it would adversely effect company earings, whether or not the idea was good for the world.

     

    It's the way the system is set up.

     

    In general, that's not possible. Almost nothing is ever invented in isolation except the nutty things like a special torch for removing nose hair. Science, particularly advanced science, is collaborative, and there is a sort of "time" for certain things to occur. Think of Tesla, for example. While he was busy developing three phase motors in East Pittsburgh, the Europeans needed the same type of devices. So, people like Ferrari invented things much like Tesla at about the same time. So, the "secret" almost always gets out.

     

    Now, of course, if there were patents, then corporations can control the use of those for at least seventeen years. But, patents are public documents. People know of their existence. If somebody like Warren Buffet knew that Exxon-Mobil was sitting on a patent for running cars on gas, he would do a hostile takeover, split the oil company from the patent and sell both separately, becoming perhaps the first gazillionaire.

     

    Privately held corporations could, of course, be immune to a takeover. But, is there any evidence that anything like this has ever occured? Read John Baez's list of clues to detect a nutty conspiracy theory.

  8. Last evening I attended a meeting that was held in a classroom of an Orthodox Jewish education center. I noted there were no powerpoint projectors, no internet, no tv, no electronics at all. There were a ton of books on algebra, calculus, statistics, history, chemistry, etc. There were a number of posters with (seemingly) student-written math questions on the wall. What do these parents know?

  9. I've seen these kinds of machines for decades and often wondered why people might think they would work. It's easy to see why somebody with no technical background might think there's magic in a magnet (Lookit, Ma, the Westie chases the Scottie!), but so many high school graduates believing in such a weird thing?

     

    Then, the other day, I picked up a university physics textbook and happened to see a picture of a bar magnet. And there were field lines popping out of the north pole and running to the south pole, and the text even described those lines "emerging" from the north pole and "ending" on the south pole. Well, "Doh!", no wonder folks believe in monopoles.

  10. The problem that you run into is that you can't gather as much radiation as you think you can, and/or you can focus it down the way you have shown. If you get a net transfer of energy between the two systems, I think you have violated at least one of those restrictions.

     

    For example, if you try to use a parabolic dish to transport the radiation, you can't assume you have a point source, which means that the radiation from the extended source isn't going to be parallel, and some of the energy will reflect back onto the emitter, representing a reduction in net power transmitted. Second (and this is mentioned in the phase space argument link), you can't focus the radiation down to an arbitrarily small size — even though you show that in one of your drawings, it isn't possible.

     

    Geez. I did a little research and then reread the OP more carefully. You're right - I was had! Oh, well...

  11. OK, I have a moment to expand on my earlier statements.

     

    I think the relevant concept here is the brightness theorem — it is not possible to increase the spectral radiance of light by passive optical devices. i.e. things don't get brighter (by he physics definition) without amplification, which requires energy input. This means, for example, that you will never be able to get an image of the sun to be at a temperature above ~6000 degrees. No matter what optics you use, and how much light you gather.

     

    Your system appears to violate this, but that's because you haven't accurately modeled it. A careful reconstruction will show that the amount of energy passing in each direction has to balance. The weakness of thought experiments is that you have to think of everything, correctly, in order for them to work. Not doing that is the hobgoblin that haunts all perpetual motion seekers (and many relativity bashers, among others). If you have a self-consistent set of rules, you cannot use them to demonstrate that there is an inconsistency. If you find one, it means you have made a mistake in applying them.

     

    The fight may not always go to the strong, nor the race to the swift, but that's the smart way to bet. The physics version is of that is that the laws of thermodynamics win, every time.

     

     

    Edit to add: Another take on this: phase space is conserved. This ties in with the "accurate modeling" in which you appear to have assumed you can concentrate the radiation in a way that isn't possible. http://www.av8n.com/physics/phase-space-thin-lens.htm


    Merged post follows:

    Consecutive posts merged

     

     

     

    Yes, there is, as I've discussed. It's not a matter of engineering. In principle it violates physical law in a few ways.

     

    Sorry. I missed the brightness violation. I suspect I don't understand his proposal after all.

  12. I think I understand your proposal. If so, there is nothing in principal that prevents your doing this, though I think you must do a lot of engineering yet. I don't see this as a lot different from the old parabolic reflector demo, and that is not very efficient and requires, I think, some sort of external energy in order to facilitate the flow of heat in a practical device.

     

    Were you to overcome the practical issues, I can readily imagine a legal quagmire over radiant rights, i.e., do you have the right to take radiant energy from the outside of my auto at an accelerated rate?

  13. I have been wanting to learn more about circuits and how do design them. I have gathered so far that this comes under physics which is why I am posting this here. I would just like to know of any good books I could read and some of the math concepts and areas that designing a circuit involves. I have scoured the Internet trying to find some information on how you design a circuit but have found nothing. Thanks for your help.

     

    If you're just starting out, there is nothing better (although somewhat old now) than The Forrest Mims Engineer's Notebook. Then actually build some of the circuits. They're easy and instructional.

  14. Take a 12 inch plastic ruler. Have a helper hold it between you almost closed forefinger and thumb such that the 0 is level with the center of your thumb.. Put a sheet of cardboard so that you cann see his hand. When he drops it, grasp it as quickly as possible. Measure where the center of your thumb is now. Work out the free fall equation for the time.

  15. A very practical way to see this is to try experiments with electromagnets, which are much easier to control. For example, you can take a long rod of iron and put identical two coils in the middle, each facing an opposite direction. You will quickly see that you can get two reasonably identical poles on the ends that are much weaker than what you have with a single coil. As you control leakage, the end poles approach zero. If you use a high mu rod and curve it back into an almost closed "C", with the ends only a few mm apart, the pole strengths will be vanishingly small.

     

    You can do the same thing with the spherical case (if you have a spare Magdeburg Sphere lying about), putting small electromagnets on the inside, all oriented out. At first, you'll get a mixture of N and S poles (One more concentrated than the other). To the extent you can make very tiny identical electromagnets, you'll begin to get overlapping N and S and you can imagine the field going to zero in your mind at least.

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