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Showing content with the highest reputation on 08/16/22 in all areas

  1. About 5,000,000,000 years from now, although it will get uncomfortable a bit sooner than that.
    1 point
  2. While it is true that UV does eventually weaken fabrics, this is usually noticeable only for things such as curtains and sofas that may be exposed to a lot of direct sunlight for hours every day, for years on end. For clothes and bed linen, i.e. the items on your washing line, you can usually ignore this, as the exposure time is a few hours per week at most. Most clothes wear out for other reasons. Regarding dryers, it is noticeable that a significant amount of fluff collects on the filter of a dryer every time you run it. This is no doubt partly human skin cells, but a lot is fibres from the fabric. My guess would be this will have more of a weakening effect than sunlight on a clothes line. In my opinion, clothes dried outside smell fresher - and of course it is more environmentally friendly as well. So personally I always dry clothes outside, when the weather permits. I make an exception for towels, which are much softer if dried in a dryer.
    1 point
  3. The ultra-violet part of the spectrum does damage cloth, in a similar way that bleach does, weakening the fabric making it easy to tear, like paper. But it's likely to be negligible for clothes on a washing line. I have a set of nice curtains, that have a white liner that hangs as an outer layer, and the liner has suffered, but the curtains have been hanging for years, and the window does get strong sunlight. You can easily rip the liner with your fingers, if you pull the curtains roughly, but the inner decorative curtain is in perfect condition. To replicate that kind of fabric weakening, I think you would have to leave the clothes on the washing line for years. The curtain liner is white, so that hasn't protected it from damage.
    1 point
  4. It's also enlarging and empowering to have the politically most powerful religion of your nation behind whatever persecution, discrimination, punitive exclusion, fact-denial and breach of civil rights you wish to commit against a minority.
    1 point
  5. Just to be clear, I have a different viewpoint on this. Modelling of expansion/compression processes assuming constant PV^k is just too good a predictor of real machinery performance to be ignored. Both P and V must be quite mappable through these highly dynamic changes of state irrespective of equilibrium considerations. It is unfortunate that thermodynamics and fluid flow are treated in most universities as separate topics since scenarios such as the OP are under the control of not just the thermodynamic equations of state, but also the appropriate form of Navier-Stokes equations. And the particular example of the OP is dominated by the most challenging form of the Navier-Stokes: that for flow of compressible fluids where both inertial and viscous terms are significant in all three spatial dimensions. Little wonder the OP is confused. And if he's doing one of the pure sciences, it's highly unlikely that he'll ever be given the analytic tools that might help him make sense of it. He would learn far more from looking at gas expansion through a porous plug. Same process of turning U to W but so little of that nasty kinetic stuff that it can be cheerfully ignored.
    1 point
  6. That'( i)s how you (would) do it. E.g. Just so you do NOT have to bother. But why should I (try to) believe you. You have given me NO proof, with your inability NOT to bother (attitude). Are all scientists so lazy (like Minkowski hinted about Physicists)? (Surely NOT!) Why should (some of the kinetic) energy leave that system? (& I DON'T accept warm, acoustic, excuses either.) (I'd like to see (simple) tangible measurements.) Oh! Abracadabra (then). (It's a mystery!) That sounds like a boring disinterest in science e.g. trying to know. A half hearted attempt to throw a few things together. You either: know; or (else) you DON'T, & you obviously DON'T, because you give me useless excuses. Sorry, other people can try to be more thorough. You DON'T even give the effort. If you (were to) say: those answers can NOT be found; then there must be a reason why. (Oh we are too feeble, (at) attempting, (to) zero_speed, =zero results. It's more difficult that c.) Disinterest is NO excuse. You also avoid commenting (up)on the (=my) initial_kinetic_energy KEi (perhaps because you habitually evade it by subtracting it away). My syntax includes KEi. (What is your syntax, if mine is NOT an extended (syntax)?) All 3 (named KEs) KEf=KEi+KEd are "kinetic_energies" ((meaning) NOT your "the"(what? _unknown), NOT mentioned f form) syntax). You can clearly see that (they are kinetic_energies) in my syntax "KE" with a subscript. There is NO difference: meaning a KE is a KE, whatever its subscript is. The KEd can (equally) accelerate a(ny) mass from zero (speed) to a (new) final_speed vf, which would finally have its own KEf(new)=KEd equal to that kinetic_energy_difference KEd. I DON'T see why you try to sell a KEd distinction (away) from any other KEsubscripted just because you do NOT know what (else) KEd is (or could be). E.g. Even though you only want KEf to be "the" (only) kind of KE (possible). It is absurd to say: KEd is NOT a kinetic_energy simply because it is NOT "the" final_KE KEf=m*(vf2-0)/2 which uses the mass m multiplied by half the final_speed squared vf2 but "subtracted by zero(_squared)"! The initial_kinetic_energy KEi=m*(vi2-0)/2 is also a kinetic_energy (just like KEf is) because its half the initial_speed squared vi2 but is also "subtracted by zero(_squared)"! The universal KE_difference formula KEd=m*(vf2-vi2)/2 is the most universal KE "definition"! There you can (=may) use any reference(_frame) speed vref=vi (below c, that) you want to be your reference speed (e.g. at rest, when identical to the initial_speed vi). If I have 7 oranges (analogy KEf) & subtract 4 (oranges, analogy KEi), then I would expect out, 3 (oranges, analogy KEd) like any reasonable thinking person. NOT grapefruits or "lemons"! (or other hogwash). That's only common sense, which seems to be missing here (in (what some people call) science). You DON'T (even) have a clue where the energy has gone, you DON'T know what it is (e.g. called, other than "difference") & yet want to be called scientists. (& you want me to believe you?) Modern physics is like modern art, anything goes, even junk. All that matters is who (e.g. what ego) has the say. I suspect you mean, the initial_speed terms (e.g. KEi) are subtracted anyway; (&) so why bother. ? Taken from a different perspective, of: if the 2 masses are on Earth & the Earth is rotating let'( u)s say vi=~1 [km/s] eastwards ((just) to keep things simple, at where they are on the Earth's surface); then they are still moving ~1 [km/s] although they appear to you as at rest. (& that KEd did NOT leave the system.) What seems (as) "at rest" is an optical delusion (of) for both: observer; & an object, having the same (=identical) speed. (E.g. Even though they are separated by a distance d.) In reality (e.g. the universe), (we know) everything is moving. Meaning NOTHING is (really) static (=at rest, with zero speed). (Everything has a speed difference wrt some other (moving) object (reference, frame).) Your "choice" of reference(_frame) (e.g. of same speed as the observed object) (help) determines whether you want to be: deceived ((in)to think(ing): ) an object is at rest (when it has the same speed as the reference_frame); or NOT! **(Sorry! (Yes) "I") Modified. (Or do you mean your quote is dishonest? Which I (rather) doubt, in preference for the former.) How else should I add (extra) comments of mine into your text? I bracketed it, to distinguish it from your original text. Dishonesty was NOT intended; only clearness of the discussion (was intended), (before getting lost again in(to) confusion between syntaxes). Should I use different brackets?
    -1 points
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