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Homework Help: Calculating the orbital Velocity and orbital period.

  1. Apr 6, 2015 #1
    1. The problem statement, all variables and given/known data
    Find the orbital velocity of the satellite 300km above the MARS surface.
    Radius: R = 3396km
    Mass of mars: M = 6.419 x 1026kg
    Gravitational constant: G = 6.674 x 10-11m3/kg/s2

    2. Relevant equations
    Vc2 = GM1/R

    3. The attempt at a solution
    I've already posted once, but need more help. If one of the threads must be deleted, please delete the earlier one.
    I don't know how to put this into a calculator to get the answer I need, because I don't understand how to interpret the many units of measurement after the G constant. After combining the radius with the orbit distance, and thereafter plugging the equation and taking the result's square root -
    My current answer is 11591.0189394, which I take to mean "11.591" km/s, which must be incorrect.
  2. jcsd
  3. Apr 6, 2015 #2


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    Staff Emeritus
    Science Advisor
    Homework Helper

    First, the mass of Mars listed in you problem statement is incorrect. The mass of Mars is 1/1000 of the value listed. :frown:


    It's not clear what you are talking about here.

    Calculators are used to crunch numbers, not units. You can do a separate reconciliation of the units to determine if you get the units of velocity (m/s). Remember to use consistent units for the values of R, M, and G in your calculations. If G has units of kg, m, and seconds, then M must have units of kg, and R must have units of meters.

    Use the correct value for the mass of Mars and calculate the orbital velocity.
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