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Space module problem

  1. Dec 12, 2003 #1
    if the command module is 60 miles above the surface of the moon it wants me to calculate the speed of the module adn the time it takes to complete one revolutionaround the mooon?

    mass moon = 7.35 * 10 to the 22 power
    radius moon = 1.74 * 10 to the 6 power
    altitude above the surface of the moon = 60 miles

    converted the 60 miles to meters which was 96540 m

    Ro = Rm + h
    Ro = 1.74E6 + 96540
    Ro = 1.74E22

    Vcm is the command module

    Vcm^2 = G * Mm/ro
    Vcm^2 = 6.673E-11 * 7.35E22/1.74E22
    Vcm = 1.679 meters/sec

    and not sure if this is right and don't know what to use to figure out the time it took to make 1 revolution

  2. jcsd
  3. Dec 12, 2003 #2
    on the time part of it should i use kelpters law?
  4. Dec 13, 2003 #3


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    Staff Emeritus
    Science Advisor
    Gold Member

    Period can be found by using this formula:


    P = 2\pi \sqrt{\frac{a^3}{\mu}}}


    Where a is the semimajor axis (the radius for circular orbits, like your problem)
    and mu is the gravitational parameter, or G*M
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