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Homework Help: Fractional Error and Differentiation

  1. Sep 17, 2006 #1
    The following was gathered in an experiment.



    r(m)----- N1------N2-----N3----N4-------N5---N_avg---delta N
    0.001---131------139---175---140-----158----148.6----15.882
    0.002----90-------96---102-----87------85----92------6.228
    0.003----52-------53----73-----65------55----59.6----8.139
    0.004----53-------53----55-----39------54----50.8----5.946
    0.005----26-------45----34 -----24------36-----33-----7.537

    delta N = stand. dev. of row

    The formula that describes the relationship among these variables is:

    Strength of source = (4.3*10^-10)*[N(r^2)/d^2] curies, where d was found to be 0.02 m and delta r = 5*10^-5 m.

    Find the error (delta s) of strength of the source.

    I took the derivative of the formula:

    delta s = (4.3*10^-10)/(d^2)*[(deltaN/N) + (2deltar/r)]

    However, I don't know where to go from here to find /\strength.

    How do I used this formula with all the individual /\N's, N_avg values, and r values?

    I did do a graph of r vs. N^-1/2 and found the slope of the regression line,

    where strength = (4.3*10^-10)(slope)^2/(d^2) and the line's slope is equal to Nr^2. (The value d is a constant here.)

    Please I really need help.:frown: Thank you for any replies.
     
    Last edited: Sep 17, 2006
  2. jcsd
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