| bio | website | kylheku.com |
|---|---|---|
| location | Vancouver, Canada | |
| age | ||
| visits | member for | 1 year |
| seen | 30 mins ago | |
| stats | profile views | 20 |
Check out the TXR language http://www.nongnu.org/txr
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7h |
answered | Quantum mechanics and everyday nature |
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8h |
comment |
Quantum mechanics and everyday nature Although a bipoloar junction transistor may require the tunnel effect to work, it is accurately described by the Ebers-Moll equations that do not make a direct reference to quantum mechanics. At some level, everything requires quantum mechanics in order to work, even a 100 kilogram mass oscillating on a big steel spring. |
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8h |
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Quantum mechanics and everyday nature By this logic, the naked eye phenomenon of gravity also requires quantum mechanics because the classical framework only gives us non-explanatory cruft like $\frac{gmM}{r^2}$, and doesn't explain why there is gravity associated with mass. |
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May 17 |
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How can I determine whether the mass of an object is evenly distributed? If you cannot tell any external difference between the black box object and a white box object of the same shape whose mass is evenly distributed, or at least no relevant difference, then can't it be concluded that the mass of the black box is evenly distributed? |
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May 14 |
awarded | Yearling |
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May 11 |
comment |
Why Won't a Tight Cable Ever Be Fully Straight? This is false. At the minimum height point, there is an infinitesimal slice of the cable which is horizontal. What's holding up every little infinitesimal slice of a cable which has nonzero thickness is not only tension, but sheer stress. |
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May 5 |
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Why isn't temperature measured in Joules? @Johannes Not any more that I would say that it's incorrect to write that "the number of centimeters is 42". :) |
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May 1 |
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Showing that position times momentum and energy times time have the same dimensions You have to be careful not to run into multiplication that is really something else in disguise, like a cross product. For instance, informally, "force times distance" could refer to torque (force at an angle, with distance representing displacement from the point of rotation or fulcrum) or "force times distance" could be work (pushing against a resistance, resulting in a displacement across a distance). In the imperial system, foot-pounds is work, but pound-feet are torque. :) |
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May 1 |
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Does the unit of a quantity change if you take square root of it? Why you sometimes see plots with funny units is that they are useful. For instance, log or log-log graphs: logarithmic frequency, versus decibels. If the given distance actually varies with the square root of mass, then this square root of mass plot will reveal that by showing a straight line. Plus any deviations from that straight line fit will be more clear. |
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May 1 |
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Does the unit of a quantity change if you take square root of it? What does the square of speed of light represent in $E = mc^2$? Or the square of velocity in the above $\frac{1}{2}mv^2$? It means that energy goes up with the square of speed, that is all. You tell me where the square root of mass comes up and I will come up with an interpretation. |
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Apr 29 |
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How can Ohm's law be correct if superconductors have 0 resistivity And that on resistance region behaves as a real resistance, for instance to an AC signal, which only cares about the changes in current w.r.t. changes in voltage. Another exammple is the input impedance of an amplifier which has a bias current flowing out of it. You can't just do R = V/I. Rather you might divide the peak-to-peak voltage of an applied signal by the peak-to-peak current variation. |
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Apr 29 |
answered | How can Ohm's law be correct if superconductors have 0 resistivity |
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Apr 17 |
revised |
Does an empty refrigerator require more power to stay cold than a full one? added 179 characters in body |
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Apr 17 |
revised |
Does an empty refrigerator require more power to stay cold than a full one? added 92 characters in body |
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Apr 17 |
answered | Does an empty refrigerator require more power to stay cold than a full one? |
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Apr 16 |
comment |
Why does my bicycle brakes squeak in the morning? This question is anecdotal. It is not universally observed that bicycle brakes vibrate or squeak in the morning. Temperature effects could be at play here. Also, surface quality change: suppose that when the bike is not in use overnight, the oxidation layer on the rim thickens by a few angstroms, but is then literally erased by the brake pads. Perhaps, also, the rubber debris which sticks to the rim undergoes some change when it is undisturbed for some hours. |
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Apr 16 |
answered | Workdone in an equipotential surface is zero? |
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Apr 16 |
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Workdone in an equipotential surface is zero? An equipotential surface is one in which all the points have the same potential. Not necessarily electric, I think. It could be, say, gravitational. |
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Apr 15 |
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What makes running so much less energy-efficient than bicycling? Agree with Steven Roose. High gears only waste |
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Apr 15 |
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What makes running so much less energy-efficient than bicycling? You're working against gravity in a wasteful way: not like an elastic bouncy ball which stores energy and comes back to almost the same height, but more like a sack of rice. |