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Homework Help: Strange question

  1. Sep 23, 2007 #1
    1. The problem statement, all variables and given/known data

    Einstein's theory of general relativity is relativistic model of gravity. "Relativistic" means it involves the speed of light, c; "gravity" means it involves Newton's constant, G. Use dimensional analysis to derive a formula for the surface area, A, of a black hole of mass M, up to a dimensionless proportionality constant.

    2. Relevant equations


    3. The attempt at a solution

    I have little idea of how to tackle this question. Any sort of help would be appreciable.
  2. jcsd
  3. Sep 23, 2007 #2
    Can anyone be of help?
  4. Sep 23, 2007 #3
    Bumping up again.
  5. Sep 23, 2007 #4
    werg lol phys 121 assignment 1 question 3 lol... hahaha waterloo university right?
  6. Sep 23, 2007 #5
    I couldn't do the last Problem... What did u get for (a) and (b)
  7. Sep 23, 2007 #6
    As far as I can tell, the idea is to propose something along the lines of:

    A= k*c^x*G^y*M^z

    Where k is a dimensionless constant.

    Then figure out what the exponents x,y and z must be so that the right hand has units of area (length^2). You should come up with a system of equations with only one solution.
  8. Sep 24, 2007 #7
    I ended by figuring it out, thanks Proggle anyway. The question is kind of obscure and the solution isn't very intuitive.

    Yes Karma I go to the University of Waterloo, I figured the same with you by your car race question.
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