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Schrödinger's hat

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About Schrödinger's hat

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    Psychic Sexpert
  • Birthday August 16

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    Brisbane
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    Everything...except cricket and football
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    Physics

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  1. Just chiming in to, hopefully, get this discussion back on topic. I've read some of the thread and only skimmed others. I am also probably not as knowledgeable about GR as xyzt is. First note, primarily to Iggy: Aside from any reasoning mistakes you may or may not have made, you appear to be using fairly specific (but not widely used) definitions of a number of terms that become somewhat ambiguous in general relativity. If these terms are used at all, they will often be context dependent and should be defined for the purposes of a discussion if they are to be used at all. Velocity (out
  2. Your copper wire is insulated so that the electricity travels around many times. This is what causes the strong magnetic field. A tube would allow the electricity to flow in any direction along the surface. Electriciy follows the path of least resistance, so it would make (at most) half a turn (or maybe one). For your second question, that is within the realm of possibility, but it would be a substantial engineering challenge.
  3. Just discovered www.maa.org/devlin/lockhartslament.pdf and thought it worth sharing/possibly stickying.
  4. People are more likely to be able to help you if you add a little more context. Maybe a few sentences around where you encountered it, or the name of the book/chapter/section/article/etc
  5. Imfataal, the reason you're having trouble is: Assuming his radix is an integer. [math]23_x = 2x + 3 = 2(x+1) + 1 = 2n+1 [/math] Is odd. [math]111100010_2[/math] is even. Either his radix is not an integer (rational solution to [math]2x+3 = 482[/math]) or there's a transcription error somewhere.
  6. Fun concept to play with: I find these help the imagination a bit. https://launchpad.net/4dtris/ http://www.urticator.net/maze/ Unfortunately it's quite hard to wrap your head around anything more complicated than simple rectangular type rooms/object. Also what you are viewing is a 2d projection of a 3d projection (or 3d slice) of a 4d scene. There are plenty of animations around youtube in a similar vein. Edit: Also worth noting is that these are euclidean spaces. There are other possible geometries, 4d (flat) spacetime is one (minkowskian rather than euclidean) and is dissimilar e
  7. Also worth noting is that your muscles consume energy both when lifting the object up, and lowering it down again gently.. This is not a necessity. A machine could be built which re-absorbed some or most of the energy it used to lift the object, it's just the way muscles work (resisting motion is close to the same process as moving in the first place). They also consume some energy when exerting a constant force (ie. just holding something heavy). A table (or even electric motor if it has some kind of lock/ratchet/etc) does not have to do this.
  8. Distance squared makes a lot of sense if you stop to think about it. If you have somekind of quantity which is conserved or preserved, and you are spreading it out over a three dimensional volume, and the source is in the middle and it's coming out in a roughly spherical shape, then your quantity will be spread over a spherical area that gets bigger at the same rate a sphere gets bigger. This rate is r^2. I don't think/know whether Newton used this reasoning (unlikely as he came up with some of the maths which was later used to prove this principle and talk about the idea of conserved f
  9. Your computer is made of that same set of elements. If I hit it with a sledgehammer, can you turn it back into a computer? Why not? The thing that's missing in each case is a very precise and hard to achieve arrangement of the components. Nothing to do with what they're made of. Re. Life, chemists are getting better at it. They are approaching creating an artificial cell from both a top down (get an existing cell and hijack it to produce a new cell to your design) and bottom up (starting from scratch). There is a way to go yet, but here is a release about creation of something ver
  10. An interpreted language at its simplest just runs through the instructions that you give it one by one, in the order that you've written them and executes them. There's usually a 1:1 or 1:many relation between things you write and actual machine code, and the order is preserved. This tends to be quite slow. If your program isn't looking ahead and finding out what bits of data it needs where, you can spend a lot of time waiting on memory or something on the hard drive. One improvement is to look ahead a few instructions and bring stuff into memory or a cache on the CPU, but dynamic languag
  11. You seem to have realised at least some of the following, but I shall state it for the record. Matlab is an interpreted language. I think modern versions have a JIT compiler and some kind of bytecode, but the importance of accuracy means they don't tend to get too tricky. Some things that may allow you to utilize more of your computer's resources: Use builtin, library and vectorised operations wherever you can, these tend to be written in C/java/fortran and are highly optimized: A.*B is far faster than doing it with a for loop. Unroll tight loops (any with <10 instructions) if you c
  12. Modern CPUs will tend to do about as much as you can fit in cache as quickly as you put it there for simple n or n^2 algorithms. Also if you don't exceed word length the computer probably won't know the difference. Also -- as Tiberius said -- there will be larger numbers on the constant and first order terms that change the results significantly for small n. Try it again with a few thousand bits and then double that (may have to use assembly unless you want to go shuffling things between different words -- not sure -- my C knowledge is rather weak).
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