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  1. J

    Questions for YOU

    Because it's fascinating! Have you ever wondered how the universe works?
  2. J

    What is the W- boson in beta decay?

    So it isn't a meson (edit: wait, stupid question as it doesn't have quarks)? By mediating the electroweak interaction, do you mean it is emitted from the neutron and then splits into an electron and antineutrino? Is it as simple as that or more complicated? If it is complicated, don't bother...
  3. J

    What is the W- boson in beta decay?

    neutron => proton + W- => proton + electron + electron anti-neutrino What're the quarks composing W-? To convert a neutron to a proton, there would need to be the expulsion of a down anti-up pair. That would mean a tad bit of mass loss, how does this work?
  4. J

    Photon's mass?

    Is kinetic energy relative? An immobile object has less KE for a relatively stationary object than a moving one, and thus has more gravitational attraction for the former? Just wanting to make sure I havn't missed the boat.
  5. J

    Speed of light in a comoving frame

    You couldn't mesure c if you were going at c, since distance and time would be meaningless for you. And if you apply the Einstein Velocity Addition (which might not be suitable for this, I guess this is only for kicks), you get c if you're heading straight for the light and infinite if you're...
  6. J

    Ball falling through hole in the earth.

    I was wondering about something similar to your problem, and I think it requires calculus and integrals (which I'm currently punching myself in the stomach for not learning in school). By the looks of your expression, you're calculating the gravitational force exerted by each kernel by its total...
  7. J

    Photon's mass?

    Ah, makes sense, thanks! What's the reason for not doing away with the concept of mass?
  8. J

    Light Refraction and Wavelength / Frequency

    In what class was that?
  9. J

    What does the photoelectric effect demonstrate

    What's the wave amplitude of a photon?
  10. J

    Photon's mass?

    Yes, I agree with gamma m as relativistic mass, but are you certain it's written that way all the time? For the relativistic kinetic energy expression: KE = mc^2 - m0c^2, where the first "m" is actually the relativistic mass I see now that this equation holds true with my supposition of a...
  11. J

    49 years ago today

    Holidays don't raise awareness, think how many kids really know that Christmas is Christ's death and resurection, as opposed to "get presents". I bet most people think Einstein was a dinosaur of the Cretaceous era, battling T-Rexs and eating fruits from trees.
  12. J

    49 years ago today

    Nah, I believe a holiday would cheapen Einstein's exploits. You can only really appreciate him if you remotely understand his theories, otherwise it's just like idolizing some hollywood celebrity schmoe.
  13. J

    Photon's mass?

    I figured m meant relativistic mass and m0 represented rest mass.
  14. J

    Why is 10 a base number?

    I wonder if the numbers of fingers on a primitive organism determines its future intelligence.
  15. J

    Photon's mass?

    If mass is energy, then energy is mass. Although the photon has no rest mass, it has energy, thus is liable to gravity. e=mc^2 hv=mc^2 m=hv/c^2, where m would be the relativistic mass? Damn my high school physics teacher for stopping me from learning this sooner! This is blowing my mind.
  16. J

    Was the entire universe a Black Hole for many years?

    What you're talking about is the Schwarzchild radius, the radius that light cannot escape. I also wonder about this, since is the universe started as a very dense, small object, how did stuff fly out? It must've been very massive to contain all of our universe's energy too.
  17. J

    Antimatter questions

    Yes, what causes a gamma to suddenly decay into a matter-antimatter pair?
  18. J

    Antimatter questions

    Matter and anti-matter collide because of usually opposite charges, right? What happens with neutrons and anti-neutrons (which I now believe in)?
  19. J

    Antimatter questions

    First, an anti-matter black hole would never exist in our neck of the woods, since there's a preference towards matter. All of it would have flown over to matter and innihilated itself. I'm not sure, but I also believe that there is no such thing as an anti-neutron; therefore, when the star...
  20. J

    This relativistic kinetic energy equation makes no sense to me

    So the kinetic energy of an object would be the second equation minus mc^2? It gives good results when I test it. My calculator has a habit of rounding off numbers, how can i fix it?
  21. J

    This relativistic kinetic energy equation makes no sense to me

    Well, I've never learned series, so that's why it flew over my head.
  22. J

    Conservation of energy relativity problem

    You use mc^2=Mgh. mc^2 is still energy.
  23. J

    This relativistic kinetic energy equation makes no sense to me

    This "relativistic kinetic energy" equation makes no sense to me Presently, I'm reading an e-book I found on the internet titled "Relativity: The Special and General Theory", which may or may not have been written by Albert Einstein. Here's the part which has me in deep patatoes: The author...
  24. J

    Force / Acceleration help

    1. The block goes 80ms^-2 to the right (let's say), and goes 9.8ms^-2 downwards. Use the pythagorian thereom to find its resulting acceleration. By finding the velocity in function of time they might want you to draw a graph... good luck, I hate doing those. 2. Objects in free fall eventually...
  25. J

    Antimatter questions

    Gammas don't have rest mass, but they do have lots of energy. Remember that E=mc^2. I'm not sure is you noticed someone mentionned electron-positron pair production; that's when a gamma ray of sufficient energy (more than double the masses of the electron and positron times c squared) splits and...
  26. J

    How is the density of a white dwarf star calculated?

    Warren, that's nuts, something I was wondering about. And Nereid, I hadn't approached the problem from such a simple direction. Though couldn't you know the rough density from only two of those variables? Thanks for a thread with a goldmine of information I'll take a week to decode.
  27. J

    How is the density of a white dwarf star calculated?

    I don't know what half of those things are, but I was looking to be able to understand the Chandrasekhar limit better. I think I'll google it.
  28. J

    How is the density of a white dwarf star calculated?

    How is the inward pull of gravity calculated?
  29. J

    How is the density of a white dwarf star calculated?

    I have no idea. And how is the pressure/force/intensity of gravitational collapse known?
  30. J

    Space shrink near black holes

    Don't take my word as gospel, cause I'm only an amateur of relativity. Time will slow down quite considerably for the orbiting junk, depending of where it's orbiting. Take earth, for example: time goes 1.000000001 times slower at its surface! Time will only freeze at the event horizon, where...
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