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Homework Help: Asteroid's orbital radius and speed

  1. Nov 6, 2004 #1
    somebody help me start this question

    The asteroid belt circles the sun between the orbits of Mars and Jupiter. One asteroid has a period of 5 earth years. What is the asteroid's orbital radius and speed?

    Thanks!!!
     
  2. jcsd
  3. Nov 6, 2004 #2
    I believe you need the mass of the sun, unless you are allowed to give your answer as a function of that variable. Use this formula:
    [tex]T=\frac{2\pi r^{\frac{3}{2}}}{\sqrt{Gm_{sun}}}[/tex]
    where G is the universal gravitational constant and T is the orbital period.
     
  4. Nov 7, 2004 #3
    is this right

    will the period be 31536000s. if it is, is this right:
    r=[T*(sqrt(GM_sun)/2pi)]^(2/3)
    [ 31536000*sqrt(6.67*10^(-11)*(1.99*10^(30)))/(2*pi)]^(2/3)
     
  5. Nov 7, 2004 #4
    Check your period calculation again. Your method looks correct.
     
  6. Nov 7, 2004 #5
    opps
    31536000*5?
     
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