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DQW

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Everything posted by DQW

  1. If it freezes at 0C and boils at 100C (leaving nothing behind), you can be pretty sure it's (almost entirely) water.
  2. Very, very rarely, the optimal solution to a discrete operations (scheduling/transportation/discrete flow control/etc.) problem is the exact solution of a diophantine equation.
  3. Especially in public key encryption (RSA, PGP, etc.) which is extensively used for all kinds of monetary transactions over the internet, including banking, e-commerce or any time you type in a credit card number on your computer.
  4. The simple method (and obvious one), on the other hand, is to get a soldering iron with temperatuer control and wait for the solder to wick onto the tip (while slowly raising the tip temperature).
  5. The standard method for determining a melting point involves putting the material (a powder of it, perhaps) in a capillary that is heated controllably to the melting temperature. The melting of the powder is clearly noticeable (better to use a magnifying glass for accuracy) by the appearance of a well-defined meniscus. One way to do this is by using standard equipment like the Mel-Temp or the Thomas Hoover apparatus. Alternatively you can use a clear oil bath that you heat on a hot-plate (with a thermometer in it) and immerse the sealed capillary in the bath.
  6. (i)The claim made was not what you state above, but rather that restricting freedoms by passing certain amendments is easier once a precedent of this nature has been set. Your statistic does not address this point in any way. (ii) Even were the claim what you claim it to be, you have not established a standard (can one ?) for the ease of amending the constitution, with respect to which you can use the cited success rate to demonstrate the historical ease or hardness of the process. I may think that twice in a hundred thousand is once too easy...
  7. Thanks yourdadonapogos ! (psst : may I just call you 'pogo', for short ?)
  8. It is negative (strictly speaking, it's component along the y-axis is negative) only if you choose the positive direction of the y-axis to point upwards. There is absolutely no reason why this is required. I did read through it . . . but did not find the part that says that the Higgs Field "can make gravity push instead of pull". But I didn't read very carefully, so I could easily have missed it.
  9. Now that's nothing but an unsubstantiated claim, and further, it's possibly no more than just your personal opinion. While I'm not arguing the truth of it, such statements mean absolutely nothing to me, if you don't provide an actual reference. It's ironic that you make such a statement in the very thread that urges members to back up claims with evidence.
  10. It is. I did, however, fail to acknowledge cronxeh by "name". I apologize. That is a spectacularly interesting looking plot, cronx. Thanks !
  11. I suspect that the "anomaly" (in the OP) may simply be that while the gravitational field might be expected to fall away as you climb down a giant crater, it is seen to actually increase...and perhaps this increase is, in fact, due to a large, high-density meteorite embedded beneath it.
  12. I know little of high-energy physics. So could you please show me where in the provided link (or elsewhere), it explains this particular concept ? I am honestly curious.
  13. This has nothing to do with one's orientation. It has only to do with the orientation of a co-ordinate axis along which you wish to project the gravitational field vector. And any orientation is acceptable.
  14. By "size", do you mean 'volume' or 'diameter' or something else ? In any case, the force between the magnets in the new configuration can be seen as the superposition of three different forces : (i) the force between magnets in the absence of the SC, (ii) the force between the lower magnet and the SC (imagine no upper magnet exists) and (iii) the force between the upper magnet and the SC (imagine no lower magnet exists) While (i) < 0, (ii), (iii) > 0, so there must be a reduction in the attractive force in the superposed case {(i)+(ii)+(iii)} compared to just (i).
  15. It's hard to tell much unless you specify the experimental conditions better (there's one particular piece I'm looking for). Think about what are all the important pieces of information you need to convey about your experiments and write down any that you've missed. (Let this serve as an exercise in communicating/reporting results of a scientific experiment)
  16. O=(0,0,0), A=(0,5,5), B=(3,2,-1) OBAD is a parallelogram; find D. As always, start from definitions - in this case, the definition of a parallelogram (and draw a picture and label it). The requirements to be met by D are : (i) OD = AB (ii) AD = OB (iii) O,A,B,D are coplanar (ie : (OD X OB) X (OB X OA) = 0) You have 3 equations in 3 unknowns. You can thus solve for them.
  17. As I've tried to say several times before, there is no ordinality to dimensions. Hence, no zero'th dimension. Things are not in some particular dimension; all things are in 3 dimensional space (or 4 dimensional spacetime, neglecting other dimensions for now). Things (actually, mathematical objects) can have different dimensions, which are only related to the dimension of the space they live in through the requirement that the former be smaller than or equal to the latter. This has nothing to do with the dimensions of the photon. Quarks and leptons are also considered pointlike particles - they are zero dimensional.
  18. DQW

    B

    Yes, the conductor and the magnet would push away from each other, stretching the spring between them.
  19. DQW

    λ

    Crudely speaking, that is correct.
  20. Someone has plotted the solution out at this site.
  21. There is no such thing as a "second dimension". And by "ours", I assume you mean 3-dimensional space. But in general, the shadow of a sheet of paper (2D object) is also 2 dimensional (unless you make the paper exactly coplanar with a point- or line-source of light). Notice that the dimensions of the shadow is simply equal to the dimensions of the space that the shadow forms on. So, if the shadow forms on a 2D surface, it will have no more than 2 dimensions. However, it is possible, as described just above, to pick the projection surface and arrange the light source such that there is a reduction of exactly one dimension. In other words, you are asking if n-dimensional space can be treated as a projection (or as you call it, a "shadow") of n+1 dimensional space. The short answer to that is yes, one can easily pick a continuous map [imath]F~:~ \mathbf{R}^{n+1} \rightarrow \mathbf{R}^{n} [/imath] that does this.
  22. Please write down what this "quation" says.
  23. Most commercial superconductors are High Tc Superconductors. They work just fine at liquid nitrogen temperatures. No doubt, you can use cheaper superconductors at helium temperatures, but then the major technological cost there will be in minimizing thermal leaks into the system - and this is hardly just a minor technicality at 4K.
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