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Help determining the Kinetic Energy of the Earth

  1. Oct 17, 2009 #1
    1. The problem statement, all variables and given/known data
    https://www.physicsforums.com/showthread.php?t=220789
    Mass of Earth= 5.98 x 10^24 kg
    Earth's period of roation = 86184 seconds


    2. Relevant equations
    KE=1/2mv^2

    3. The attempt at a solution
    To be honest, I have no clue how to do this question. I am royally confused on this one. I've asked some friends of mine who are in the same class as me and they aren't sure how to do this question either.

    Any help is appreciated
     
  2. jcsd
  3. Oct 17, 2009 #2

    mgb_phys

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    Science Advisor
    Homework Helper

    Welcome to PF.
    I'm assuming it means the KE of the Earth around the sun. It's a bit of a silly question because you have decide which motion to include, just the Earth around the sun or the earth and sun around the galaxy (at a million miles a day) or the entire galaxy moving etc.
    But anyway that's just confusing you .....


    Think of the earth as a car going around a circular track.
    How long does it take the Earth to go around the sun?
    Whats the circumference of the orbit (hint you will need the Earth-Sun distance)
    From these you can get the speed then use the equation you have
     
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