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Showing content with the highest reputation on 10/07/19 in all areas

  1. 2 points
    One thing to remember, if someone suggests that humans didn't evolve on Earth but go one to suggest we interbred with a species, ie Neanderthals, that did evolve here then you can be sure who ever is suggesting this has no idea what they are talking about!
  2. 1 point
    Build your formulae in one of these and copy/paste into SF. https://latex.codecogs.com/ or http://www.sciweavers.org/free-online-latex-equation-editor
  3. 1 point
    d(flux)/dt gives an induced voltage (with a sign) So putting this into mathematical form [math]d\Phi = - BdA[/math] divide both sides by dt [math]\frac{{d\Phi }}{{dt}} = - B\frac{{dA}}{{dt}}[/math] Where A is the area enclosed by the (triangular loop) Faraday's law. [math]E = - \frac{{d\Phi }}{{dt}}[/math] Where is is the voltage generated in a wire at right angles to the field Now draw some positions of the blue wire in at varous times. Also extend the velocity vector of the blue wire in both directions. What do you notice about the triangular areas so formed? Can you connect this to the above in terms of the velocity of the blue wire? The point of the similar triangles is that you don't need any actual values of area, ratios will do. One further note. E is generated only in the blue wire because it is the only wire moving. The black wire is stationary in the field so no voltage is generated in this one. The circulating current in the loop is entirely due to the motion of the blue wire. One final twist - is the blue the blue wire motion at right angles to the field, in accordance with Flemings rule?
  4. 1 point
    ! Moderator Note As my assumption that this was homework appears to be wrong, I have moved this back to the original forum.
  5. 1 point
    https://byjus.com/maths/area-of-similar-triangles/https://byjus.com/maths/area-of-similar-triangles/ You will need both lengths and areas
  6. 1 point
    IIRC there are problems like this in Halliday & Resnick (and no doubt in the later versions) with a rectangular cross-section. Making it a triangle just adds a little extra geometry to the mix.
  7. 1 point
    I had thought this was not homework for a formal course you are doing, online or off. How are you getting on with the geometry? When you come to it how do you think the slant angle will affect Flemings generator rule ?
  8. 1 point
    The way I understand it, the bent wire is immobile versus B while the skewed one, of identical nature, moves and is in contact with the bent one. d(flux)/dt gives an induced voltage (with a sign) while the summed wire length gives a resistance. Neglecting the self-inductance (="the field produced by the wires themselves") you get a current. Note that 8T is unusually strong. It take a superconductor or a small duration. 32ohm/m is much even for a resistor wire.
  9. 1 point
    You can actually do the experiment with a compass... ! Moderator Note I warned you I would close this.
  10. 1 point
    My suggestion is to do the geometry first. Look up the properties of similar triangles if you don't already know them Use these properties to find out the rate of increase of the area of the triangle and the lengths of the 2 wires that make it up. Then worry about the induction.
  11. 1 point
    That’s a start. That gives you the voltage. The resistance will change over time as the wire moves. Solve for I.
  12. 1 point
    ! Moderator Note Claims without evidence are bad enough, but yours contradict observation. Provide a basis for your claim, or this will be closed
  13. 1 point
    A good summary of just quite how ludicrous this book is here: http://www.scicommbobulate.com/blog/2014/2/18/week-6-book-review-humans-are-not-from-earth-by-ellis-silver Other animals are prone to overheating (lizards have to get out of the sun when they have warmed up) and sunburn. Or because we walk upright. I suggest you assume every claim in your post is wrong and do some research with reliable sources to find more accurate information. It is unmitigated drivel
  14. 1 point
    It's also easy to refute most of the points raised. Many are just wrong, for example: Allergies are observed in most mammals. We are most likely to spot them among our pets https://www.msdvetmanual.com/dog-owners/skin-disorders-of-dogs/allergies-in-dogs https://thepigsite.com/disease-guide/sunburn-heat-stroke
  15. 1 point
    ! Moderator Note I am closing this thread, if for no other reason than because I am sick of closing reports on it (but also because it’s complete and utter nonsense and doesn’t belong here).
  16. 1 point
    Pulling this post back to where I can find it to add Yukawa couplings details this weekend [math]\mathcal{G}=SU(3)_c\otimes SU(2)_L\otimes U(1)_Y[/math] Color, weak isospin, abelion Hypercharge groups. Couplings in sequence [math]g_s, g, \acute{g}[/math] [math]\mathcal{L}_{gauge}=-\frac{1}{2}Tr{G^{\mu\nu}G_{\mu\nu}}-\frac{1}{2}Tr {W^{\mu\nu}W_{\mu\nu}}-\frac{1}{4}B^{\mu\nu}B_{\mu\nu}[/math] Field strengths in sequence in last G W B tensors for SU(3),SU(2) and U(1) Leads to covariant derivative [math]D_\mu=\partial_\mu+ig_s\frac{\lambda_i}{2}G^i_\mu+ig\frac{\sigma_i}{2}W^i_\mu+igQ_YB_\mu[/math] Corresponds to [math]G_{\mu\nu}=-\frac{i}{g_s}[D_\mu,D_\nu][/math] [math]W_-\frac{I}{g}[D_{\mu}D_{\nu}][/math] [math]B_{\mu\nu}-\frac{I}{\acute{g}}[D_\mu,D_\nu][/math]
  17. 1 point
    ! Moderator Note Then this is a pointless thread for a discussion forum.
  18. 1 point
    Maths is not simply about having a formula and substituting values into it. Trying to learn lots of formulae is likely to lead you into difficulty in the long run. Understanding what you are doing is far better. Note: I am just about to apologise to another member in another thread for not reading his post properly and therefore not understanding and thus saying something silly and using the wrong formula.
  19. 1 point
    So this is a tricky bit. The criminal justice is currently disproportionately affecting African Americans negatively because the implemented policies (at least individually) were race-blind. A key example is the high penalties for crack vs cocaine. And it works on all levels, African Americans are more likely to be stopped and searched, for example, and were more frequently convicted for possession of drugs, despite the fact that drug use is pretty much the same between black and white communities. The only policy managing to adjust it a little bit was to take those statistics showing that for similar offenses African American were more likely to be receive more severe punishments. On the policy level it has led to some adjustments, e.g. looking into how judges punish folks depending on ethnicity, for example. A criminal justice reform that does not explicitly address these biases could result in a reversal of these band-aid policies. In other words, just to reform the criminal justice system does not automatically benefit African American, especially if race is not a factor. Considering in the past the criminal justice system was able to overpenalize black communities without implementing race, I am not sure that enacting new policies will automatically improve the situation. Specifically, it is recognized that the system has systemic issues that run across racial boundaries and while laws (of course) where all race blind. What some suggest (and maybe that is what you mean) is to look into laws that are overapplied to African American (say prosecution of youths as adults for minor crimes). In that case it would benefit African American, but the changes would not be race blind per se. After all they would need to take the racial disparities into account in order to implement them properly. I.e. I do not see a way to address racial inequalities without targeting them specifically. However, if you mean with race-blind that the laws should not target race in language, then that is rather trivial, AFAIK laws are not allowed to discriminate by race so there should not be any to begin with. Affirmative actions are something else entirely and are only allowed under a relatively narrow legal window (specifically, allowing employers to create a diverse environment, should they choose so). Edit: I should also add that criminal justice specifically also overpenalizes Hispanics, which would be another factor to take into account.
  20. -1 points
    This isn’t a religious site, off topic. Man that first sentence looks like you fired up the blender. I think you lie about having a P.H.D Mordred. I think you use false credentials to feel important.
  21. -1 points
    Only a guilty minded man is that defensive. Not going to speak to it, huh. Simple from here and year.
  22. -1 points
    It means a lot to be a doctor and what your doing is insultive.
  23. -1 points
    Blender again, please leave. I think your knowledge of physics is trivial.
  24. -1 points
    Watch out tho, the Dungeons and Dragons people might come. Ya, use your level five spell on them.
  25. -1 points
    Not your friend, leave please. Your disgusting. I’ve reported that your pretending to be a doctor. Please leave Are you gay, I’m not interested, please leave my post.
  26. -1 points
    Your not here to talk Physics, you barely know basics, your here for me write intelligently and you heckle. Until mommy takes your Dungeons and Dragons board away. This guy is heckling me, squatting on my post, claiming to be a P.H.D, Help (Reported) Your here unwanted citing rules, please leave, not your friend.
  27. -1 points
    This theory likens our solar system to a light bulb with the sun being as the constant emittence of a filament and frames the Earth as a light bulb within a light, having itself a measure of constant emanation of light as well as capacity to store absorbed light from the sun. Additionally the theory frames thought to show that every heavenly body capable of producing light has atmosphere, and those objects incapable of constant light eminence have no atmosphere. ...the scientific cast of mind examines the world critically, as if many alternative worlds might exist, as if other things might be here which are not. Then we are forced to ask why what we see is present and not something else. Why are the Sun and moon and the planets spheres? Why not pyramids, or cubes, or dodecahedra? Why not irregular, jumbly shapes? Why so symmetrical, worlds? If you spend any time spinning hypotheses, checking to see whether they make sense, whether they conform to what else we know. Thinking of tests you can pose to substantiate or deflate hypotheses, you will find yourself doing science. — Carl Sagan This theory explains that the heavenly body that enfolds a secondary heavenly body within its circumference of constant emanation has gravity over that now orbiting satellite. Here you can imagine a bubble pushing into the outer layer of a larger bubble and for a short while sharing a part of their circumference with each other until the smaller has become whole yet inside the larger. At this point the internal dynamics of the larger center of force will prescribe the orbital path of the inferior center of force.
  28. -1 points
    And your evidence that it is not...... is that you accept without question the Illusion or delusion that magnetism encircles its current as did predecessors who accepted that the Sun circled the Earth. If Oersted did not have a compass on his desk and he observed co-parallel conductors attracting, then he would have logically concluded that a magnetic wind flowed with the currents not encircling. The flow between them requiring less energy.... My evidence is that it is obvious and logical whereas the alternative is an irrational act of faith. The measurements don't alter but the reasoning does.
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