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Showing content with the highest reputation on 04/21/19 in all areas

  1. 1 point
    Interesting discussion, and while this has got way too philosophical for me, let me make a small offering....... Space is what exists between you and me, and Earth and the Moon. If space did not exist, then everything would be together and we would be as we were before the BB. Time exists to stop everything from happening at the same instant. If there was no time, we wouldn't be here and the same applies that we would be as we were before the BB. Here I submit the following..... "The views of space and time which I wish to lay before you have sprung from the soil of experimental physics, and therein lies their strength. They are radical. Henceforth space by itself, and time by itself, are doomed to fade away into mere shadows, and only a kind of union of the two will preserve an independent reality". — Hermann Minkowski, Which in my opinion tells me that spacetime is simply the framework against which we locate events an describe them in terms of length. breadth, height and time. Spacetime is also defined by the following facts. [1] the speed of light is invariant. [2] Intervals of space and time, vary according to different frames of references, but spacetime is invariant.[3] Gravity is the geometrical warping/mis-shaping of spacetime in the presence of mass/energy. All are real as I see it, space, time, spacetime, despite not being physical.
  2. 1 point
    Some much better and more satisfying to have done (most of) it yourself. +1
  3. 1 point
    Ahh I see, and to explain, my only confusion in the beginning was the reaction. I must divide the final precipitate weight by the molar mass of AgCl which will give me both moles of Ag+ and Cl-. From there I can divide the moles of Cl- by 2 since MgCl2 requires 2 Cl- ions to form. So this would then give us the total moles of MgCl2, from which we can divide the weight of the moles by the weight of the original sample, which is 1.0 g. I think this is right, and I will post back whether it works or not. Aha, so it worked. My answer came out to .475 * 100 --> 47.5% of the original sample. Thank you all for the help, I understand this much better now!
  4. 1 point
    What does the excess mean? John Cuthber has already told you that the precipitate is all silver chloride. Can you see why? If not does anything stand out below? Did you look up solubilities as I suggested? In solution there are (before precipitation) Cations : Mg2+, Na+ and Ag+ Anions : Cl- , NO3- Possible salts and solubilities MgCl2 very soluble NaCl very soluble AgCl low solubility Mg(No3)2 very soluble NaNO3 very soluble AgNO3 soluble So your 1.43 grams of precipitate is made up of what? Can you think of the next two steps?
  5. 1 point
    Also, are you aware of the relationship between the amplitude and the intensity of a sound wave? Hint: they are not directly proportional.
  6. 1 point
    Original Post (first post) in this case but it can also mean Original Poster if that's the context.
  7. 1 point
    The classical quantum debate’s head rears once more.
  8. 1 point
    here is brief explanation: the moment of inertia (on its own axis)of cat is different on the branch compared to moment of inertia when falling . so does the angular velocity. hence to conserve angular momentum it twist itself..
  9. 1 point
    Hmm, so to be sure I am not misunderstanding your question, but you wonder how the initial eye development (for instance) would start? I will give an example (which most likely isn't true, but I feel like it should give a conceptual idea of progression from 0% to 0.0000001%): Let's say we have, through random variation, the first production of a protein which imports calcium through the membrane of the cell. After a while, through more variation this protein is changed ever so slightly and now reacts to light; only letting calcium through after it has been hit by light, this change does not provide any benefit yet but let's now say that high concentrations of calcium lead to inhibition of the movement apparatus, now this organism will move towards light as the movement apparatus on the "dark" side will be more active due to lower amounts of calcium. Maybe places with light have a larger amount of food and this organism will be fitter than its peers. That could be a conceptual beginning of the eye, slight changes which lead to more and more complex mechanisms that react to light, with each step of the way increasing the fitness or maintaining the fitness of the organism. Slowly over time this organism may be able to evade predators more easily due to its eye or find food better than without an eye. Does that answer your question or did I completely miss the mark here? -Dagl Edit: fixed sentence
  10. -1 points
    Recall that Strange made an unqualified "(the rest of the universe would look increasingly blue-shifted)", which is wrong. That's what I responded to. Sure within BH in-fall scenario an in-faller will encounter a mix of transverse and radial light ray components. The former becomes an increasingly minute contribution as in-fall proceeds to small r, since only the radial component of photon momenta get gravitationally boosted as in-fall proceeds. Taking as a given the formal GR calcs of Hamilton are indeed valid, it's (sort of) obvious from his color coded movie that for the vast majority of in-fall, redshift entirely dominates. And btw the reason all that is moot is that even assuming GR as Truth, contrary to many claims, it's no 'optical illusion' that the in-faller freezes at the EH - as seen from outside. The logical consequence of having coordinate c -> 0 at 'EH' is that from in-faller's 'stopped coordinate-time clock' pov the entire rest of universe is infinitely old at the moment he/she hits the 'EH'.