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studiot last won the day on August 3

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    Somerset, England
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    applications of physical sciences
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    Semi Retired Technical Consultant

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  1. Within the Earth, the gravitational acceleration increases linearly as you move from the centre to the surface. So this has the form g = jr, where j is a positive constant. An interesting side effect of this is that if you dropped a capsule into one end of the tunnel it would execute SHM about the centre. Of course, above the Earth g diminishes in accordance with the nomal inverse square law. But you don't need this. I am working on the density ATM, so these relationships can be combined
  2. Gosh I though chickens came from KFC. Silly me.
  3. There seems to have been a slip of the keyboard there it should, of course be a + b = 6 and a + b = 7
  4. Yes this is your basic problem, right at the beginning. The basic fallacy is trying to combine two incompatible statements and preceeding from there. That will always end in tears many famous paradoxes and other trick questions can be resolved by realising this. Mathematically it is rather like a lazy teacher who wants to go off for a smoke so he sets the class the following problem and offers a prize for the solution when he returns. Sove the following simultaneous equations for a and b. a + b = 6 a + B = 7 You said The ship is travelling in the universe The ship is 10 m long. So the universe cannot be '1m long'
  5. I have done quite a bit of both acoustic emission testing (your technique) and (ultra)sonic propagation testing over the years. It is still an up and coming technology. We still have much to learn, there have been good successes as well as spectacular failure with these techniques. https://www.astm.org/DIGITAL_LIBRARY/STP/PAGES/STP15782S.htm A technique allied to this is called acoustic signature analysis. In my day processing the huge amounts of data required was a difficulty, as was calibrating a measuring device using these principles. Neural networks are a modern method of attacking the data processing aspect, the second one still remains. I suggest you look around the existing subject more widely as the applications are already legion, but there will be a ready market for genuinely better equipment in this field. As a liquid velocity meter, how is your gadget affected by water quality eg suspensed material in the water ? Ability to distinguish this could be a useful variant if it can provide an alert to contaminants in the piping.
  6. In Physics ? Interestingly in German the terms im kleinem : often translated from german textbooks as in the small and im grossen : often translated from german textbooks as in the large are used for locally and globally In Mathematics the term local <some property> applies in some neighbourhood of a point but not for all points in the entire set. That is reserved for global, where the property may be applied to any and every point in the set without restriction. A slight point here arises because strictly the term neighbourhood may apply to the whole set as well. So really local on its own is incomplete. It requires a statement of restriction for that.
  7. These were just examples, there are many shapes of wiggly lines. But I beg to differ that these are unimportant. If the lines represent energy what about the local maximum of activation energy ? And if we move to multivariable situations what about saddle points/ Are there any maximum / minimum points there? This represents a whole vital part of Physics.
  8. This may be your thread, but your latest post moves the goalposts. Before you can discuss time in universes we are not in, you have to prove that the time in these universes is the same as time in out universe. Difficult since we have not yet arrived at a definition of time in our universe.
  9. Nah, Trumps has a new infallible strategy for reelection. Appoint Alexander Lukashenko as campaign manager.
  10. As regards local v global I have The plot of y = - x2 has a global maximum, but no minimum. The plot of y = x3 - x2 has no global maximum or minimum, but has a local maximum and local minimum.
  11. Yes see your doctor. There are some parasites which lay eggs that hatch and burrow out to lay more eggs that hatch and burrow............ Thus there is a time interval between appearances. But this is not a medical diagnosis site so I repeat the ScienceForums prescription See your doctor.
  12. Let us go back to the conditions you specified in the beginning of this thread. I am assuming a spherical earth to take advantage of symmetry. So the tunnel has two ends, both open to the atmousphere at r = R. The pressure at both ends must be equal and equal to the pressure of the atmousphere at the surface of the Earth. If they were not equal then air would move along the tunnel to make them equal. If they were not equal to the atmouspheric pressure then air would move into or out of the tunnel until they were equal. This pressure is denoted PR So you have one value for PR, given by the integral from r = R to r = the edge of space given by the conventional formula for the atmouspheric column above any point of the surface. You can choose a constant gravity and density or assume some meteorological function to get this figure. You get a second value for PR by developing a formula for gravity inside the Earth, which must equal the first value, as already noted. So you can form an equation between these two for your answer.
  13. Which is more complicated than what I said, but OK it will do. I can see that The pilot does (can't) measure 'the universe' he can only measure the distance to something that is moving relative to him Remember all movement is relative. Movement without a reference point is meaningless. His frame includes his ship and the whole rest of 'the universe'. Here is an alternative look at the problem. Let us suppose that when he is travelling at full speed, he passes by an object exactly 1 m long when it is at rest in his frame. What will he see ? He will see an incredibly foreshortened object, many many orders of magnitude smaller than 1m, which he can measure as he passes by first the back, then the front and knowing his speed relative to the object he can recover the 1m rest length, if his super computer onboard is better than wolfram alpha. Now scale that up to the whole universe. Does this help?
  14. OK so be it. So you have the volume of the 'reservoir' available to each well. You are given the density, porosity (phi if I am not mistaken) and specific heat of the rock and injected fluid. So you can do a "heat gained by fluid = heat lost by rock" calculation to establ;ish Tprod, which I assume is the eqyilibrium temperature produced. Thus you can substitute into the first equation (HIP) given. Where do you think the permeability comes into things ? You need to show some working, we don't do the calculations for you, but might help you check them.
  15. Thanks for the replies and the support. Here's a couple of thoughts to add If a function vanishes at some points i.e. is zero, does that make it local or non-local at these points?
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