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Homework Help: Uncertanty in a Cylinder.

  1. Feb 11, 2009 #1
    1. The problem statement, all variables and given/known data
    9.The diameter of a cylindrical piece of copper rod was measured at a 24.8 +/- 0.5mm with a vernier caliper. Its length was measured at 135 +/- 0.5mm with a meter rule.

    a. Calculate the percentage uncertanty in the diameter.
    b. Calculate the percentage uncertanty in the length
    c. Calculate the percentage uncertanty in the volume of the cylinder.
    d. Calculate the absolute uncertanty in the volume of the cylinder in mm^3

    2. Relevant equations
    %U = AU/Measurement (atleast thats how i do it)
    V = Pi x r^2 x l
    Thats all i know.

    3. The attempt at a solution
    I figured out:
    A. %U = 0.20%
    B. %U = 0.37%
    C. %U of V = 0.77%

    But I've got no idea about D. Needs to show full working out.
  2. jcsd
  3. Feb 11, 2009 #2


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    Staff Emeritus
    Science Advisor
    Homework Helper

    Welcome to PF :smile:

    Before doing D, I'll suggest re-doing A and C. Post back here, then I can help with D.

    (B is correct, by the way.)
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