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Error Analysis

  1. Sep 13, 2009 #1
    1. The problem statement, all variables and given/known data

    Find the accepted value of g

    2. Relevant equations

    (sigma)(g) = |g|[(sigma(L))/|L| + 2 (sigma(T))/|T|]
    Acceleration due to gravity for a pendulum broken down.

    3. The attempt at a solution

    I really do not have a clue. If I had to guess, I would say 2. Can anybody please offer me some help with this problem?
  2. jcsd
  3. Sep 13, 2009 #2


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    Please write the expression for g in terms of L and T?

    Then write the expression for the error of g, or σg, or better σg2.

    Is one given the errors (σ) of measurement?
  4. Sep 13, 2009 #3
    Would it be...

    sigma g/g = sqr[((sigma L)/L)^2 + 2((sigma T)/T)^2]

    gbest = (4pi)^2 x L/T^2

    The first one would give the errors of measurement?
  5. Sep 13, 2009 #4


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    Is this the formula that one is given?

    If so, the what is the expression of g in terms of the other variables?
  6. Sep 13, 2009 #5
    O.k. I totally confused...let's start from the beginning. The original equation was:

    g = 4(pi^2)L/T^2, then, to the best of my knowledge I'm supposed to break down the equation to:

    g = 4(pi)^2LT^-2, and this is where I get confused because I've never dealt with something like this before, and I wasn't given much instruction. i also appreciate you being patient with me.

    So, after this I assume I'm supposed to break down the equation into an error equation:

    sigma g/g = sigma (4)/|4| + 2(sigma (pi)/|pi|) + sigma (L)/|L| + |-2|(sigma (T)/|T|)

    Now, I get this equation from an example but I get confused on what to do with it after this point. I know 4 and pi are constants and can be removed from the equation but I don't really know where to take it from here.
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