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Finding the Mass of a Planet

  1. Mar 2, 2010 #1
    1. The problem statement, all variables and given/known data

    As an astronaut, you observe a small planet to be spherical. After landing on the planet, you set off, walking always straight ahead, and find yourself returning to your spacecraft from the opposite side after completing a lap of 25.9 km. You hold a hammer and a falcon feather at a height of 1.35 m, release them, and observe that they fall together to the surface in 25.7 s. Determine the mass of the planet.

    2. The attempt at a solution

    I don't even know where to start. Any pointers?
     
  2. jcsd
  3. Mar 2, 2010 #2

    rock.freak667

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    Homework Helper

    Try using this and a kinematic equation to find the acceleration. Then just use

    g=GM/r2
     
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