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Homework Help: Find mean distance from asteroid Icarus to the sun

  1. Oct 14, 2004 #1
    Ok, I keep trying to do the following problem:

    ----The asteroid Icarus orbits the Sun like the other planets. Its period is about 410 days. What is its mean distance from the Sun?
    (Hint: You can derive the mean distance with the paramters known for the Earth: Period of the earth = 365 days Mean distance from the sum = 1.5e8km)----------------

    Ok, so, using Kepler's laws I took 410 days and put it to the (2/3) power...and I got 55.2 AU...one AU (astronomical unit) equals 1.5e8 km...so I multiplied 55.2 by 1.5e8 km and got 8278414420 km....or 8.28e9 km.....but the computer program says I'm wrong. Does anyone know what I'm doing wrong? Thanks.
  2. jcsd
  3. Oct 14, 2004 #2
    Hint: Look at your units.
  4. Oct 14, 2004 #3
    which units? if one AU=1.5e8 I can multiply 55.2 by that to get the answer, right?
  5. Oct 14, 2004 #4
    What units are you supposed to use in kepler's third law?
  6. Oct 14, 2004 #5
    oh do i have to convert 410 days to years? like 1.123 years?
  7. Oct 14, 2004 #6
    oh that worked! Thanks for your help :D
  8. Oct 14, 2004 #7
    Yup! That's exactly right.
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