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timo

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Everything posted by timo

  1. Don't be silly. Everyone knows that if you don't use the terms "quantum fluctuations", "energy level", "wave function", "uncertainty", "Einstien", "Dark Matter", "Feynman", or "Christmas Tree" then it is not physics.
  2. That depends what you consider a "reliable source". I have no doubt about the source's reliability when it comes to asking if the person mentioned as the author actually exists and if he actually wrote the article himself. I also have no doubt that the author actually is serious about what he writes. So in that sense the source is reliable. For me, a quick look at the homepage of "Prespacetime Journal" ("about" section (edit: it did not seem to work when I tried, but now it seems it actually does), the "editorial board", ... come on, already the name of the journal sounds like "crackpot inside") tells me that I won't bother reading any of their "publications". But you are of course completely free to judge otherwise. In the end, I can not say anything against the content of the paper you dug up (since I didn't read it ).
  3. 1) Relax. This forum is not a chat room, and tends to be much slower than most other forums you may be used to. Many of us are really old grandpas (25+ years old), and prefer a slower pace of discussion. 2) I actually never even tried to answer your questions, I merely told you that you will not find the kind of people whom you wanted to address your question to (people who went through school and university education in the US and at least hold a PhD in theoretical particle physics or string theory) in this forum. I can of course comment on your question (and won't stop anyone else to do so) if you want to. I just don't have the competence you were asking for. 3) I am not from the US. Good public universities for a B.Sc. degree can be found in Europe. 4) From my experience of reading a bit on physicsforums.com every idiot and his mother think that their live is forfeit if they do not go to one of the famous engineering schools in the US (for a degree in theoretical physics ...). Considering the number of applicants that probably result of this hype, my first-order approximation about your chances would be "zero".
  4. My comments on the article are: 1) "published" in "Prespace Journal". 2) Factors of "\frac{1}{4 \neq}" that are presumably meant to be "\frac{1}{4 \pi}" 3) Many quotations from famous physicists. Interesting references section. 4) You can find many more articles of the same author on viXra.
  5. I don't understand what you say here. Dunno. I'm active almost exclusively here, and never been registered at any other forum than this, physicsforums, and a programming forum.
  6. I know of only two people on sfn who do work in string theory or theoretical particle physics on a PhD+ level. Neither of them seems to post here, anymore. The two people still posting here that may come closest to that are not from the US. In other words: You may be better off asking your questions in a forum with a larger physics audience, e.g. www.physicsforums.com (but even there most replies are likely to be from fellow students who merely pretend to know what they are talking about).
  7. Earth sphere rotates within a single rotation of Earth - known as baby,child, parent and grandparent. Name your 4/16 greatgrandparents. Your own people will kill you to prevent this 'Forbidden Truth Cube' from ever being known. Socrates was killed to hide Truth from public. 1-corner god is a Cubic creation. Academia is a counterfeit representation of value. Humans are educated stupid as teachers lack intelligence. Truth is 100%, belief is 50%.
  8. The study actually seems to contain other TV news, too. Fox is outstanding in the sense of making the last place in both questions about Libya and Syria.
  9. Kind of. Sometimes. But your statement doesn't seem to make too much sense in wave mechanics, either: What is an "energy level" in wave mechanics, and why is it like "the amplitude"? And what is "the amplitude" (say, of the wave f(x,t) = e^{-(x - at)^2} - e^{-(x - bt +3)^2}), anyways? EDIT: Sorry for being a bit rude (I actually skipped the really rude part before submitting this reply). But I think that if you ask a question about something that interests you and use what seems to be inappropriate terms, then if someone asks you to specify those terms a wish-wash non-answer like "aren't particles being described using wave mechanics?" is not appropriate. We could of course boil the whole issue down to "you know nothing about classical mechanics, so don't even bother asking questions about QM", which is a formally correct answer. But that is probably not what you are interested in. You should consider issues with using inappropriate terminology and concepts (that you don't even seem to know what they mean) as serious indicators that something is fundamentally missing, rather than twist, bend, and glue analogies and non-understood concepts to a rubber-band ball of hollow phrases.
  10. I don't even know what that is supposed to mean. What is the "energy level" (the energy?) and what is the "amplitude" (something related to a wave function of an object?)?
  11. Well, "3 choose 13" is not exactly a proper sentence. "You use 13C3 to choose combinations for 3 from a pool of 13" comes closer to a proper sentence (still sounds odd to me, but I am not a native speaker, anyways). How would you then calculate the number of possibilities to choose two people out of a set of twelve? Btw.: No need to rush the answer. I'll go to bed soon, anyways.
  12. If your focus is on preparing for an exam then train under exam conditions - possibly even time constraints. Your student who doesn't know "2*4/5" out of the top of her head will surely find a way to evaluate it if there is no pocket calculator at hand - and she better finds that way before the actual exam. Since I've never been to the US, less taught physics or math there, I can of course not comment on the general situation of "students don't learn anything anymore". I do realize that some of the experiences you describe in your OP are strange or disturbing. But you should (a) keep in mind that not all of these issues apply to all students, and (b) for each of them ask yourself if they really matter in the end. If your strongest argument against using a calculator is that the calculator is not allowed in the exam, then perhaps using a calculator is not that much of a real problem. Considering the in my eyes more real problems like students not knowing that a force that is perpendicular to displacement does no work: You sometimes do have to tell students (or colleagues ) things that they are actually supposed to know (*). "You passed an exam about it so you must know it" is a very typical teacher attitude. But I also find it very arrogant and think that it does not take into account that students are human individuals with their own ideas and their own ways to connect information, and may therefore put different priorities (than you) on the lot of material that they are presented(*). Accept it, and see it as your chance to get the point across better than that last guy who obviously failed. A good teacher must pick up their students where they stand, I think. Please note that I am not trying to attack you here. It's more like playing the devil's high-school student's advocate. It's pretty easy just to tune into the "the kids of today are all so stupid" canon and tell stories about stupid students encountered. But without reflection it is also pretty lame to do so. (*) Two weeks ago I helped two of our grad students who had struggled for an hour to compile some code. Took less than one minute to find the solution on Google. And "yes", grad students are expected to be able to use Google without supervision.
  13. I know it as "13 over 3", but whatever. Why do you use it? Yes. And if you can answer my previous question and then reread my previous post the expression should be obvious. Yes. Isn't that the same question as above? You're welcome. You should try to answer my question to you, though. I don't ask them for fun or because I wouldn't know a correct answer to them myself. I'm asking them because you need to be able to answer them to understand the solution to your questions. I do know that students are often interested in having the answer, only, and do not really bother understanding them. But I also know that understanding the answers is actually the important part of homework.
  14. What is "13_C_3" and why do you use it to solve the first question? The number of committees that John is on in the number of combination that you can make out of John and two of the other twelve people. And "yes", your method to evaluate the last question seems okay. Can you explain why you substracted the number of committees that they are both on (which is correct - I am just checking if you understood what you did)?
  15. I don't really see a problem with students using calculators if it is a valid method to solve the problem at hand. I have no idea what an "AP class" is, btw ("Advanced Physics" ?).
  16. I am pretty sure you do not need to buy a specialized program for what you want to do. Even if Excel won't do, gnuplot should suffice in any case (and is free). My main question remains: What do you want to do? To give three options: 1) Calculate A(t) for a given A0 and T1/2? 2) Calculate T1/2 from a given A(t)? 3) Something else? For case 1) try the following off-my-head guide: Enter the times t into the first column. Click on the top box in the 2nd column. Click on the "=" or "f(x)=" button in the symbol bar. Enter the formula where "t" is replaced with either "A1" or "$A$1" (you'll have to try which it is). The correct A(t) for the time in A1 should appear in B1, thereafter. Click the lower-right corner of the field B1, and drag down. This should copy the formula to all other fields in column B.
  17. timo

    Vector spaces

    You should have read the homework rules which, if I remember it correctly, state somewhere that you are not supposed to be given the answer without showing what you have tried. Despite my hint you haven't even listed up the vector space axioms, less showed your attempts to test them. I don't think there is much to help you at this point.
  18. The answer to your question is "yes", but that is probably not what you really wanted to know. Perhaps you should be a bit more detailed about what you intend to do.
  19. timo

    Vector spaces

    Just check if the axioms of a vector space are satisfied.
  20. Not according to any mainstream physics I was aware of. The time coordinate is considered as real-valued in all models I have encountered (*). Strictly speaking that of course is only a choice that works well on all accessible scales (say from picoseconds to a few billion years), and that outside this scale things could be different. Over the years my attitude towards such things has become "possibly - but why should I care?". (*) That is not correct. I have encountered many models with integer-valued time (e.g. a calendar). But in all those cases it was clear that the discrete time is only an approximation to simplify things, not a correction.
  21. I faintly remember that we have a rule for the homework help section that you should not only copy-paste your exercises, but also comment on each what your thoughts about it are, what you tried to answer them, and where you got stuck. There are a lot of people here who are competent discussing these homework questions with you, but there is little point in just explaining the answers to you (that is the job of your teacher). So please share your own thoughts about these questions with us.
  22. Because each "\\" prints one "\". The reason is that you need what I believe is called an escape character, which is a character indicating a "command" rather than a normal letter. By "command", I mean an output that you cannot properly represent in your source code editor. For example, a carriage return is "\n" (go ahead and printf "this\nis\nan\nexample\nwith\nmultiple\nlines" to test it). The problem is that if you want to print the actual escape character on screen you cannot simply write this character, because the language would expect it to indicate a following "command". The solution is to make printing of the escape character a "command", too. So the command for a new line is "\n", and the command for a backslash is "\\". This is, by the way not unique to C. If you ever use latex (e.g. for mathematical formulas in this forum) you may encounter the same concept, there.
  23. Depends why you want to do physics. If you like to think about the universe and how the world works then go for physics as a hobby - professional physics is not really like that on an everyday basis. If you like to build experimental devices, test for yourself if the equations you were being told are correct, and enjoy solving mathematical puzzles and problems then a proper university education in physics may be the better route. Particularly logic skills (not to be confused with intuition, which in everyday language is a synonym) and an understanding of the basic principle of natural sciences (that experiment and not good arguments ultimately dictate what is correct and what is wrong) are hard to obtain by yourself. While studying physics and working as a physicists required some discipline to really do the workload you have, I think having hobbies such as painting suit such a disciplined life very well to get your head clear and keep mental balance.
  24. That is very close to a very dangerous assumption: Do not fall for the fallacy that a good programming background was very helpful for a career in computational physics. Good programming knowledge is very helpful to get positions up to post-docs - every group leader likes members who shut up, work on the project they are being given, and don't need constant supervision. But beyond that level, programming skills (beyond those that everyone in the field has anyways) are of little help, in my opinion (*). Professor positions in physics are not given for being a good programmer, they are given for being a good physicist. Also, irrespective of prior programming experience, I have never encountered a physics PhD student who was seriously limited by his programming skills. People are limited by not knowing enough physics, math, experimental techniques, and current development in their field. There is of course nothing wrong with being more competent in computer science - just don't expect it to give you a real edge. (*): I recently encountered someone who disagreed with that and claimed that technical details like the order of loops in your code are important in computational physics. It is not in what I do, but obviously cannot speak for all of computational physics. Ironically, that someone works in finance because he couldn't get a position in academia.
  25. For creating threads in the format of a fictive letter to a dead person I recommend speaking of yourself in the third person.
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