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swansont

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Everything posted by swansont

  1. I've linked to a number of credible (IMO) sources who disagree. Do you have anything to support your contention that it's a liquid?
  2. The solid parts, too. But since the liquid parts are more free to move about, we see the water tides. But the solid parts move by about 30-50 cm each day.
  3. One effect would be that somebody would shoot C. Montgomery Burns.
  4. 1 Watt = 1 Joule/sec, and 1 Joule = 1 kg m2/sec2 moving 100 g a distance of 1 m in 1g = .1 kg * 9.8 m/sec2 * 1m = .98 Joules It's close, but is not the way the Watt is defined.
  5. Glass doesn't flow. It's thicker at the bottom because it was installed that way - old glass wasn't necessarily of uniform thickness. urban legends page U Alberta page yet another site
  6. A longer arm has more mass, and so has more KE that can't be transferred to the projectile. That's one reason that the trebuchet works better - longer moment arm with essentially no increase in mass.
  7. But less common that solar eclipses.
  8. That's because the objects have equal masses and the collision is pretty much elastic, so KE is a conserved quantity along with momentum. If the collision isn't head-on, or the masses are unequal, the conservation laws dictate that the projectile will retain some KE. Under some circumstances, it can end up with more than it started with (target moving toward projectile).
  9. No, because the resistance goes up with more wraps, so the current goes down for a fixed voltage.
  10. Basically, yes. If you know which slit it went through, you no longer get interference - all the quantum effects go away.
  11. The types of magnets used for mounting things on refrigerators are pretty weak and the field doesn't extend very far. Chances are any deflection you are seeing is an effect of the airflow.
  12. Perpetual motion. And energy being conserved isn't just a fad, it's a consequence of the laws of physics not changing with time. Check out Noether's theorems - all conservation laws have a corresponding symmetry, and vice-versa. (e.g. conservation of momentum for translational symmetry, conservation of angular momentum from rotational symmetry)
  13. Understand that physics in general and QM in particular typically require years of study to understand. The prospect of an understandable five-minute summary that has any depth or breadth is an unreasonable expectation. This stuff ain't easy.
  14. I disagree. Hydroelectric plants, for example, do this all the time. There are some that will pump water up into a reservoir to be used at a later time at peak electrical demand.
  15. It's only 24 hours at the poles (actually 23 hours 56 min). You have to multiply 24 by sin(latitude) to the the period for a Foucalt pendulum.
  16. Sorry, but this is watered down to the point that it's wrong. Things are either stable or they aren't, so I object to "more stable" - you can have degrees of instability, but not stability. Gold has stable isotopes - to say it "decays slowly" and imply that's why it's not used for fission is incorrect. Gold doesn't fission because that wouldn't tend to release energy. Plutonium and Uranium fissioning often yield nuclei that are even more unstable (i.e. shorter half-lives) which is why nuclear waste is a problem. On to an explanation for fission- Nuclei are made up of charged protons and neutral neutrons. There are two forces inside a nucleus: the electrostatic forces of repulsion between the protons and the nuclear force of attraction between all of these particles. The nuclear force wins, because it's stronger, but it only acts between particles that are close to each other. The repulsion acts between all of the protons. So there's energy stored (not unlike a spring that's compressed) when you have a lot of protons around - which happens in heavy nuclei like Uranium and Plutonium. Hitting them with a neutron can make them distort to the point that they can break apart and become two smaller nuclei - the nuclear attraction is about the same, but there's less energy tied up in the electrostatic repulsion. You also release a couple of neutrons, which means theis whole process can be sustained in a chain reaction, which was described earlier. Other nuclear reactions release energy as well, such as alpha and beta decays. If you want explanations of these, just ask.
  17. I just glossed over it - I didn't see where he drefines what unintelligent design would look like. Until you define that properly, how can you differentiate it from intelligent design?
  18. The question states that you are to find the power of the motor, which is related to the work it has to do.
  19. No, because that term would go away if the coefficient of friction went to zero, and you still have gravitational potential energy for which you must account.
  20. You want the total, not just in the x-direction. Since the net acceleration is zero, you can get the power with P=Fv, and the net force is the vector sum of the weight, friction, normal, and rope. You want to solve for the force from the rope. Alternately, you can solve for the work done by friction and potential energy in a given amount of time, since you have a constant known speed. Work/time = P
  21. Right. Sundials don't work because the sun is not exactly overhead at noon most days of the year, and they just plain aren't going to be precise enough. Plus, you want to be able to make the measurement at your convenience.
  22. Please correct me if I'm wrong, but as I understand it homeopathy is basically extreme dilution of a solution, well past any meaningful concentration compared to contaminants in the water, and often past a factor of 1024 per mole, meaning there's a good chance the water doesn't have any of the original solute in it.
  23. A problem is that saying "I did X and then I felt better" relies on the logical fallacy of post hoc, ergo propter hoc. Happened after, therefore was caused by. You may drink water (homeopathic remedy) and feel better, but you don't know that you wouldn't have felt better anyway. Most common ailments improve with no real action on our parts - just time. That's why conventional medecine requires double-blind tests to show that there's a real, causal link between the remedy and the cure. Show me a homeopathic remedy that's passed this hurdle.
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