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Homework Help: Solar system

  1. May 25, 2008 #1
    1. The problem statement, all variables and given/known data

    the image below shows the Moonat perigee and apogee. Measure the diameters for the two, and determine the ratio between perigee and apogee idstance.Based on your result, what is the eccentricity of the Moon'orbit? Compare your value with the Moon' s mean orbital eccentricity(e= 0.0549)

    2. Relevant equations
    i have already measured diameters of apogee and perigee, 6.00cm and 13.00 cm(i am not sure about these two numbers.)

    3. The attempt at a solution
    based on the formula e= (1-b^2/a^2)^0.5,where b is the sei-minor axis...i am very confused about this question.
    any help is appreciated.
    Last edited: May 25, 2008
  2. jcsd
  3. May 25, 2008 #2


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    Staff Emeritus
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    Gold Member

    You need to find a formula that relates eccentricity to apogee and perigee rather than to the semi-major and semiminor axi. (Or find a formula that relates the apogee and perigee to the semi-major and semi minor axi.)

    I'd also double check your measurements. (they seem a bit off to me.)
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