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Genady

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Everything posted by Genady

  1. I'd like to know what you've posted, but I can't, because a) I'd have to follow the link, which is against the rules, and b) the link is a URL shortener, which is not advised to follow.
  2. They have visited here two days ago
  3. Step-by-step derivation here: How to Derive the Speed of Light from Maxwell's Equations: 7 Steps (wikihow.com)
  4. Here are some lists: Category:Piscine and amphibian humanoids - Wikipedia or more generic Category:Mythological aquatic creatures - Wikipedia
  5. About the wing: the point is to create a difference in pressure above and below. The pressure does not need to decrease on both sides. It can stay the same below the wing and decrease above the wing. So, it does not contradict that moving fluid does not necessarily have a decreased pressure. However, I think that your common sense understanding of Bernoulli's principle is incorrect. There are many solid explanations of it online. There are also various mathematical forms of the Bernoulli equation. E.g., If a pump makes a work, -ws, then the velocity, V, can change without a change in the pressure, P.
  6. Yes. Why not?
  7. No, I don't see why causing the fluid to move would decrease the pressure within the fluid. The Bernoulli's principle doesn't say so, AFAIK. I think you're right and I see where some decrease in pressure above the sinking piston might come from. As the piston moves down and the fluid above it moves down with it, a level of the top surface of the fluid is lowered because it takes time for the fluid sipping in from below to fill the gap. Thus, the height of the fluid column above the moving piston is smaller than "normal", and the pressure is lower accordingly.
  8. Oh, such a pleasant read for somebody who cannot eat any dairy and who grew up in a greens eating culture. Thank you!
  9. You haven't met the requirement to be paid attention to. Thus, you are placed in the ignore list.
  10. Inside the flow, where there are no other sources of energy, the pressure where the fluid moves faster is lower than the pressure where it moves slower. How it relates to the pressure outside the flow, is another question.
  11. I think I made a mistake there by jumping to conclusion that it will reduce a pressure on the wall.
  12. Regardless of the wall being vertical or horizontal, if the fluid moves by external force, this movement does not reduce the pressure. Yes, perhaps you better go back and find where this idea of the reduced pressure came from.
  13. The alphabet based writing, i.e., writing based on how words sound, appeared about 4000 years ago. Before that, writing did not represent how the words sound, but rather represented objects that the words refer to. The alphabet did not evolve from separating sounds, but rather from the previous symbols representing objects. For example, a letter for the sound "A" evolved from a symbol that represented an object for which the word started with the sound "A". History of the alphabet - Wikipedia
  14. No, there is not. The rotating paddle wheel will circulate the water but will not decrease the pressure.
  15. I think we can say any of that or something else, e.g., "the force is from the wall", - as long as we understand the mechanics of it.
  16. If "they" are so advanced then they are over an original excitement of discovery and exploration and perhaps just trying to dump their criminals away, like British used to send their convicts to Australia.
  17. We measure the downward pressure times the area and this is equal the weight, if the wall moves with a constant velocity. The brief moment of the reduced pressure will last while the wall accelerates from the resting state to a constant velocity. When the velocity is constant, the pressure will return to be equal the weight of the fluid divided by the area of the wall, i.e., not reduced.
  18. These words might have a common origin since both English and Persian languages have a common ancestor, Proto-Indo-European language, aka PIE. However, I think that a connection is much more convoluted than the sounds being similar or "squishy and mushy". Look at the etymology of the English word: (worm | Etymology, origin and meaning of worm by etymonline)
  19. I think, they do in the first approximation. But generally, they are more complex because there are other internal forces in the fluids.
  20. Yes, at any point in spacetime where the two waves are present, the resulting field is the sum of two fields. Each one of the two waves continues unchanged. They do not "collide". Their effects simply add up.
  21. Yes, they just go through each other. No, they don't interact.
  22. Maybe it is in principle impossible.
  23. If it were possible, then police work would be very easy. Take a piece of a suspect's skin and listen to all their past conversations.
  24. No. I don't think we do. Even if we could, we would recover a sum of all sounds that hit the object throughout history. That would be just noise.
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