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Homework Help: Solve for the length of a cylinder

  1. Jan 13, 2010 #1
    1. The problem statement, all variables and given/known data

    Gold, which has a density of 19.32 g/cm3, is the most ductile metal and can be pressed into a thin leaf or drawn out into a long fiber.If a sample of gold with a mass of 2.850 g is drawn out into a cylindrical fiber of radius 2.800 μm, what is the length (in m) of the fiber?

    2. Relevant equations

    Volume of Cylinder= (PI)(R^2)(h)

    3. The attempt at a solution

    1. I converted the density from g/cm3 in g/m3.
    D= 19320000 g/m3

    2. I use the equation V=M/D to solve for the Volume of the cylinder.
    V=(2.850g)/(19320000 g/m3)
    V= 1.475155E-7 m3

    3. I converted the Radius from um into m
    2.8 um * (1m/10E-6 um)= 2800000

    4. I set the Volume of the cylinder equal to (PI)(R^2)(h) and plugged in the radius in m
    (PI)(2800000^2)(h)= 1.475155E-7 m3

    5. I then solved for h and got the answer of: 5.989E-21 (rounded to 4 SF)

    I have gotten that answer over and over but our online physics homework system WileyPlus says it is incorrect. Any ideas where I went wrong?
    1. The problem statement, all variables and given/known data

    2. Relevant equations

    3. The attempt at a solution
  2. jcsd
  3. Jan 13, 2010 #2


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  4. Jan 13, 2010 #3
    ha THANKS! As always, a retarded mistake.
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