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Homework Help: Dimentional Anaylsis: Solving for Revolutions

  1. Sep 2, 2012 #1
    NASA's Cassini mission to Saturn released a probe on December 25, 2004, that landed on the Saturnian moon Titan on January 14, 2005. The probe, which was named Huygens, was released with a gentle relative speed of 31 cm/s. As Huygens moved away from the main spacecraft, it rotated at a rate of seven revolutions per minute.

    How many revolutions had Huygens completed when it was 160 yards from the mother ship?

    I know the answer is 55 rev; however, I got a completely different answer. I solved for the answer this way:

    160yd*(3ft/yd)*(12in/ft)*(2.54cm/in) = x

    I then divided x by 31 cm/s, and multiplied it by 420 rev/s.

    Any help or advice would be much appreciated. :smile:
  2. jcsd
  3. Sep 2, 2012 #2
    How can something that does only 7 revolutions in 60 seconds do 420 revolutions in 1 second?
  4. Sep 10, 2012 #3
    You're right. I don't know what I was thinking! I did figure out that I needed to divide 7rpm by 60s and multiply that number by 471.948s, which gave to 55rev. :smile:
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