Recent content by Rear Naked

  1. R

    Clarification needed: u-sub requires combining 2 constants

    Homework Statement Evaluate ∫-x/(x+1) dxHomework Equations The Attempt at a Solution I do a U-sub u=x+1 du=dx x=u-1 -∫(u-1)/u du -∫[u/u - 1/u] du -∫1 - 1/u du -[∫1du - ∫1\u du] -[u - ln(u) + C] ln(u)-u+C ln(x+1)-(x+1)+C ln(x+1)-x-1+C I combine -1 and C into a single C to get the...
  2. R

    Undergrad What is the trajectory of an object thrown within a rotating centrifuge?

    Is this true if the craft travels along the axis of the hoop?
  3. R

    Undergrad What is the trajectory of an object thrown within a rotating centrifuge?

    Why would you need two rotating parts? You could just put two opposite facing rockets positioned on opposite sides of the craft. Start em up, wait until the adequate rotational velocity is reached, then shut em off.
  4. R

    Graduate Kenneth Krane's Modern Physics muon example (SR)

    I meant 3.0e^8 because final equation involves using 2.2us. Doesnt that require the answer to be two sig figs? 0.999978c = 2.999934 E8 m/s Which should be rounded to 3.0 E8m/s (due to the 2.2us) Actually, I knew the problem was simplified in the half life aspect. :-) Thanks for...
  5. R

    Graduate Kenneth Krane's Modern Physics muon example (SR)

    This is the frirst SR problem in his book. I think the question is flawed. The solution assumes a speed of 3.00 E8 m/s to calculate Δt=333us since it traveled 100km. Next, 333us and 2.2us is used to solve for velocity using the time dilation formula. Velocity is reported to be .999978c.This...
  6. R

    Does michio kaku hate leonard susskind?

    Hard to argue with logic like that!
  7. R

    Deja Vu Theory / Some Direction Needed

    Can we stimulate these areas of the brain to induce feelings of deja vu or love? Do we know what causes these hypersynchronous or hyposynchronous firing of neurons?
  8. R

    Near-Death Experience: Investigating Theoretical Implications

    Cool dream.
  9. R

    Graduate How Does an Infinite Static Arrangement Collapse Under Gravity?

    Ok, that makes sense. Thank you for the reply.
  10. R

    Graduate How Does an Infinite Static Arrangement Collapse Under Gravity?

    How can I make sense of that then? Newton's logic seems flawless to me.
  11. R

    Graduate How Does an Infinite Static Arrangement Collapse Under Gravity?

    This is what my intuition tells me. This is the quote from Hawking that confused me: So, the qualifiers are that the stars must be "roughly uniformly" distributed? It seems strange to not further clarify...especially when he says they will "always collapse."
  12. R

    Graduate How Does an Infinite Static Arrangement Collapse Under Gravity?

    Can anyone explain this to me? If we have an infinite amount of balls arranged in a kind of cubic matrix, in an infinite and static space...how the heck would that collapse on itself due to gravity? Thanks folks
    • Rear Naked
    • Thread
    • Gravity Homogeneous Infinite Isotropic Static
    • Replies: 8
    • Forum: Cosmology
  13. R

    Undergrad Infrared Radiation: Where Does It Come From?

    I think we are talking about different things. To help determine the identity of an unknown chemical, we can do an IR analysis. We shine IR radiation through a chemical, and the bonds between atoms will absorb IR radiation at specific wavelengths. I don't know about atoms giving off IR...
  14. R

    Undergrad Infrared Radiation: Where Does It Come From?

    is this true? In chemistry, IR spectra show bonds, not individual atoms... Like Useful nucleus said...the wagging, etc. of the bonds.
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    Graduate How do physicists use redshift to determine the expansion of the universe?

    If light cannot reach us from the unobservable universe, then nothing can. Therefore, nothing we ever do can have any effect on the unobservable universe, and vice versa.