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Homework Help: Earth mass and density problem

  1. Mar 4, 2017 #1
    1. The problem statement, all variables and given/known data
    The Earth is about 12.70 km in diameter. The Earth’s average density is about 5.5 grams cubic centimeter. A nucleon (the main constituent of an atomic nucleus) has a mass of about 1.67 x 10⁻²⁷ kilograms. If the Earth’s mass is entirely due to its nucleons, how many nucleons are in the Earth?

    2. Relevant equations
    Volume = 4/3pi*r3

    3. The attempt at a solution
    radius =6350m
    volume = 4/3pi*(6350)3 = 1.07 *1012
    density =5.5g/cm3 =5500kg/m3
    Earth's mass = density*volume
    =5500kg/m3 * 1.07 *1012
    =5.899 *1015 kg

    number of nucleons= 5.899 *1015 kg / 1.67 x 10⁻²⁷
    = 3.53 * 1042

    This answer is wrong but why is it wrong?
    Last edited: Mar 4, 2017
  2. jcsd
  3. Mar 4, 2017 #2


    User Avatar
    Gold Member

    Uh ... seriously?
  4. Mar 4, 2017 #3
    lol, thank you, I thought something was fishy :smile:
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