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Homework Help: Propagation Method - Calculating Absoute/Relative/Percentage Uncertainties.

  1. Sep 28, 2008 #1
    1. The problem statement, all variables and given/known data
    Hi everyone, I'm having some homework trouble, and am hoping you can help me out. Here's the question.

    QUESTION: Using the propagation method for calculating uncertainties, calculate the absolute, relative, and percentage uncertainty for the volume of the cylinder and the uncertainties for density for each of the different methods used.

    Mass of Cylinder: 20.6g +/- .1g
    Composition of Cylinder: Copper (8.87g/cm^3)

    Method 1: Meter Stick
    Average length: 2.07cm
    Average Diameter: 1.16cm
    Uncertainty: +/- .05cm

    Method 2: Vernier Calipers
    Average Length: 2.142cm
    Average Diameter: 1.211cm
    Uncertainty: +/- .0025cm

    2. Relevant equations
    Propagation of Uncertainties:
    Code (Text):
    1. If S=A+B (ΔS=ΔA+ΔB)
    2. If D=A-B (ΔD=ΔA+ΔB)
    3. If P=A.B
                    ΔP    ΔA   ΔB
                    __ = __ + __
                     P     A      B

    4. If Q=A/B
                    ΔQ    ΔA   ΔB
                    __ = __ + __
                     Q     A      B

    5. If P=A^N
                    ΔP      ΔA  
                    __ = N___
                     P        A  
    Percent Error: [Accepted - Measure] / Accepted *100

    3. The attempt at a solution

    I've read the rules, and I understand you arent supposed to ask for help if you dont at least try, but I honestly have no clue where to begin. If anyone could help me start out I'll quickly respond with my best effort. But I am currently totally lost.
    Last edited: Sep 28, 2008
  2. jcsd
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