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5614

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Everything posted by 5614

  1. Can't help you really, but did you try using Google Scholar: http://scholar.google.com
  2. It's a question of money and personality, I think. If you're good at working by yourself then this is probably a good option. Although if you've got loads of money then, I suppose, you have nothing to lose by getting a tutor as well. But this is a "want" not "need" case. If you're bad at studying by yourself, fear (with reason) that you could miss something or are generally bad at getting yourself to work then maybe a tutor would be a good idea. This is more of a "need" case. I suppose those are two extreme cases; but you seem quite a clever person and I'm sure you can analyse yourself and answer your own original question.
  3. You should just be able to place the .ppt file, or a shortcut to it, in the Startup folder. For XP: Start > All Programs > Startup
  4. After a bit of thought I'll expand my answer to say this: In any undisturbed room (ie. where the air molecules can be assumed to be moving totally randomly, Brownian motion) when you play music the room will heat up. The reason is that whilst the particles moving towards the speaker will slow down, this will be cancelled out by the particles moving away from the speak which speed up. The inbalance that causes net heating is where particles are moving very slowing relative to the progessing wave. These particles (whether they're moving slowly towards or away from the sound wave) will all speed up. Thus there is a net energy gain. I suppose maybe this is stating the obvious... but anyhow!
  5. In your equation you said P=F/S, where P is pressure, F is force and S is the area over which the force is applied. What he was saying was that using S for area is an unusual notation... normally people use A for area, so P=F/A is what people expect to see.
  6. Ah yes, of course. It's obvious if you look at it from a graphical viewpoint. Clearly an identical post-two-slit system can be obtained from two separate single slit diffractions. And then all you need is for those two waves to be in-phase and then you have something identical to the normal two slit experi. Thanks!
  7. Can I just check I understand this correctly: You have two single slit experiments, each with their own light source, brought close together. Then the single slit diffraction pattern, from each of the two single slits, will interfere and a "normal" double slit diffraction pattern will emerge?
  8. It's not such a stupid question after all though. If you consider this: further the thought experiment to light, then you get into interesting relativity. We know that light in a vacuum always travels at the same speed of light, called 'c'. But if the man on the train sees it go up, straight, but we see it go diagonal down then we see it move further (a diagonal from ceiling to floor is longer than a straight line)... but how can the light move further, in the same time (from top to botton) when we both measure the speed of the light as the same. How can it go further, when it's travelling at the same speed? The answer gets into a bit of basic relativistic mathematics, although the simple answer is that because the train is moving the train's (from our, on platform point of view) time is moving slower. This is known as time dilation. A stationary observer (you on platform) sees a moving observer's (a train going past) time going slower. But the man on the train thinks that he is stationary. If he looked outside he would think the man is moving past, and he is still. This is how relativity is sometimes introduced to university students for the first time. Well, near the very beginning anyhow! If you're interested, and willing to possibly get a bit confused(!), then I'd sugges reading into a bit of basic relativity. It is kinda interesting!
  9. E=mc^2 says that energy and matter are different forms of the same thing. Ice and water are different forms of the same thing, but that does not mean ice is water. And yes, like water E=mc^2 does mean you can convert mass into energy, this is what a nuclear bomb does. Note that the 'm' in that equation is an object's "rest mass". That is the mass when the object is stationary. A photon is never stationary, therefore it is said to have zero rest mass. Then you say E=mc^2, m=0 therefore E=0. And that is where the longer equation, which Swansont mentioned comes into play. E^2 = p^2c^2 + m^2c^4 where p is momentum. Again this is a weird atomic/quantum momentum and not the classical 'mv' thing. For a photon m=0 but p is a number, and thus it does have energy. In lightning the energy comes from the fact that the fast moving electrons can release, or cause atoms it passes by to release, photons. Again as Swansont said, a lot of energy from the Earth is radiated back out in to space, mainly in the form of infrared radiation. If more energy comes in then goes out then the Earth heats up, this is known as a "greenhouse effect".
  10. Right you are Taq. If you make some sound waves in a room then these waves are transmitted through the air by the atoms moving around and knocking into each other. This means the atoms will have a higher kinetic (moving) energy and thus a higher temperature. However remember that air molecules, in an average room, would normally move around quite a lot anyway. Whilst the sound waves will make them move in a specific direction (away from the sound source) their actual speed might not increase much, if at all. An example would be if the all the air was blowing towards the sound source. Then by turning on the music you are pushing the air molecules in the opposite direction to where they are going - you are slowing them down. In a room the molecules will all be moving in random directions, but I use this "wind example" to demonstrate my point. If there is any effect it is very small, and you wouldn't measure it normally. As for theoretically, well, yes it would increase the temperature, unless what I said in my 2nd & 3rd paragraph is significant.
  11. I think it would work in theory, but that in reality you would get a tiny current and it would not be anything impressive.
  12. That's not true. The closest to power transmission through the air was big sparks, and they're not an efficient way to transmit energy, the distance is limited and it is not very safe. You cannot pass electricity through the Earth. Have you got a reliable source that backs you up? NB: There will, sadly, be many websites which agree with you, hence I asked for a reliable one. The crap you read on the Internet about free energy and cold fusion etc. is generally not correct. The Internet is a wonderful source of information, but remember that not all of it is true. In fact, a lot of it is not true. Be careful what you believe.
  13. That is strange, although I've had a similar experience... I suppose it is most likely to be some sort of corruption within the file. Some kind of intereference within the wire would seem a good explanation. Unless of course that scratching noise was always there you just never heard it, say if the EQ was setup differently. But then you would probably here scratching on other tracks, so maybe not! Try transferring one again and see what happens.
  14. Happy holiday and happy new year to everyone!
  15. A general solution would be this: [math]ax^2 + bx + c \to a(x + \frac{b}{2a})^2 - \frac{b^2}{4a^2} + c[/math] Applying this to the original equations gives: [math]2(x-1)^2 + 4[/math] howareyou: I advise that after you complete the square that you expand the brackets, and see what you're missing. Although this relies on you knowing the first part of the general solution, which is the a(x + b/2a)² then once you enter that you can expand that and work out what to add on the end.
  16. herme3; you forget that when Vista is released on a full scale the amount of viruses and malware targetted specifically for Vista will skyrocket. Whilst IE7 may block a few things at the moment, that's because nothing is targetting it. The only things that is testing IE7 is IE6 malware. When IE7 comes out with Vista then, and only then, will IE7-specific malware be developed. At that point lets see how well IE7 stands up to life in the big bad world. I might dual boot Vista so I can play Halo 2. But otherwise I have no intention to use anything other than WinXP.
  17. That's just how it works. If the universe didn't store the information of all the particles in it then the particles would not have any information to base their existence on, they would not exist. Although I do not think that was what Davies meant when he said: "it turns out that you need so many numbers to describe that state that it would exhaust the capacity of the entire universe to store it" I think he is basically saying is that the mathematical description of the 400 entangled particles is absolutely massive. They contain more information than you can possibly imagine. To try and paint an image of this unimaginably massive amount of data he said that storing this amount of data would overfill the capacity of the entire universe. It's just meant to emphasise a point. No. His point is that when you start entangling more than 400 particles in one quantum computer these 400 entangled particles can hold massive amounts of information. This could be used to build a quantum computer capable of doing very large calculations very quickly. If you only have 12 entangled particles (12 is currently the largest quantum computer), then there is only a relatively small amount of information stored between them. They can make a quantum computer, but it is not anything extraordinary as far as it's power is concerned. Davies is saying that when you reach 400 entangled particles the power of a quantum computer made from them starts getting interesting. A quantum computer is supposed to make what you or I would call a 'normal computer' look very slow. So by "getting interesting" I mean that, according to Davies, when you reach a quantum computer containing around 400 particles the power of that computer is, well, getting powerful. I have no idea how a 400-particle QC compares to an electronic computer speed-wise... but obviously Davies feels it is some kind of landmark. Whether that's becoming faster than, the same speed as or slower than an electronic computer I don't know.
  18. Yes, from programs like Restoration: http://www.snapfiles.com/get/restoration.html which is reviewed as "free, simple but with limited recovery capabilities" to more advanced programs which you need to pay for, such as DiskInternal's Uneraser: http://www.diskinternals.com/ there are many programs which are designed to recover deleted files. The reason these programs work is because when you delete a file from your computer it is not really deleted. What actually happens is that the space on the hard drive is marked as empty, so something new could be written onto it, however until something new is written there the old data remains. And this is the crucial point; if you've used the computer a lot (or even at all) since the temporary backup files created by Word were deleted, the chances are they have been overwritten by the computer. The standard advice when you accidentally delete a file is stop using the computer, at all costs. Do not use it, for anything. I've never had any luck with these programs, it was earlier today that someone asked me about them, he had tried using one of these programs and had no luck. I do know someone who recovered some music he had accidentally deleted, but generally they don't seem too efficient. Obviously you could pay a professional to do recover a file. Again this is not guaranteed, but they seem to have some special method of recovering deleted, lost, corrupted or encrypted files. I'm sure you've heard of the police or FBI recovering deleted and encrypted files from computers and using that as evidence in court, if they can do it (and remember the criminal probably went to extra measures to hide, delete or encrypt the data), it is theoretically possible. More generally you can always advise people to backup. I think that's one of those pieces of advice that many people give out, and not many people listen to. Sure some people backup data at the end of a working day, but even that would not have helped your mum. I'm afraid to say I think she was just unlucky, and I'm sorry for you, but you just have to live with it, life is harsh sometimes!
  19. I think 400 is just an example, but it is chosen for a reason. 40 would have been too small, and wouldn't have made the point he made in that quote. Whilst 4,000 would fit the quote, it is unnecassarily big. I looked at the link, and would like to quote one other part, it helps answer your question: Was it just the number 400 that puzzled you?
  20. From the first paragraph of the site you linked to: As observers in different frames disagree on an observation, surely it is frame dependant.
  21. bascule is not a "hit and run" guy! Maybe he doesn't have a reply, or his query is answered or he just forgot about this thread... but he's a respectable guy, been here for over a year and a half, almost 3000 posts (nearly all of which are quality posts) etc.
  22. Normally when you quit Word it will automatically delete all temporary backup files, leaving your single saved file. If she had have deleted the file then there's all sorts of programs that are supposed to recover deleted files, not that any of them have ever worked for me, however she actually overwrote the file (with all 10 pages) with a new one (with only 2 pages), so I don't think it is possible to recover.
  23. And this is why accurately modelling a solar system with multiple bodies, over a large period of time, requires a complex program running on a supercomputer.
  24. If you put it like that it doesn't sound so bad! So is the car actually totalled this time? And sorry to hear about your bad luck.
  25. I was aware of the issue of 0^0 being undefined when I posted the solution, however as it's: x^y - y^x = x + y you would get (0^0 - 0^0) and can you not argue that that is equal to 0?
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