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Kinetic energy of plate tectonics problem

  1. Mar 4, 2017 #1
    1. The problem statement, all variables and given/known data
    One effect of plate tectonics is that the North American continental plate moves across the Earth’s surface at a speed of about 1.15 cm/yr. The North American plate has an area of about 35 million square kilometers, an average thickness of about 25 km, and a density of about 3 g/cc. What is the kinetic energy associated with this movement?

    2. Relevant equations
    0.5mv2

    3. The attempt at a solution
    volume=area*thickness
    volume= 35 *109 * 25000 = 8.75 *1014 m3
    density =3 g/cc = 3000 kg/m3
    velocity= 1.15cm/yr = 3.697*10-10 m/s

    mass = density * volume
    mass= 8.75 *1014 m3 * 3000 kg/m3
    mass = 2.625 * 1018 kg

    kinetic energy = 0.5mv2
    0.5 * 2.625 * 1018 * (3.697*10-10)2
    = 0.179 Joules
    My answer is marked wrong but what's wrong with it?
     
  2. jcsd
  3. Mar 4, 2017 #2

    gneill

    User Avatar

    Staff: Mentor

    Check your conversion from square kilometers to square meters for the area.
     
  4. Mar 4, 2017 #3
    Check your unit conversions.

    EDIT: Beat me to it.
     
  5. Mar 4, 2017 #4
    oh I see my mistake now, thanks for your help
     
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