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Circular motion of the moon

  1. May 6, 2015 #1
    1. The problem statement, all variables and given/known data
    The Moon’s nearly circular orbit about the Earth has a radius of about 385 000 km and a period T of 27.3 days. Determine the speed of the Moon. Determine the magnitude and direction of the Moon’s acceleration.

    Mark Criteria: A)determining the correct period of motion in seconds
    B)determining the correct radius of motion in meters
    C)determining the correct speed in m/s for
    D)determining the correct magnitude of acceleration
    E)determining the correct direction of acceleration

    2. Relevant equations
    V= 2(pie)(R)/T

    ac = V^2/R

    3. The attempt at a solution

    A) 27.3 days (60s)(60m)(24h) = 2.36 X 10^6s
    B) 385,000 km = 3.85 X 10^8m
    C) V= (2)(pi)(3.85 X 10^8m)/(2.36 X 10^6s)
    = 1.025 X 10^3 m/s
    D) ac = (1.025 X 10^3)^2/ (3.85 X 10^8m) = 2.7 X 10^-3 m/s^2
    E) Towards the center of uniform circular motion

  2. jcsd
  3. May 6, 2015 #2
    I've been posting multiples of threads in the homework section, and I'm little worried if I broke any rules/regulation. I'm just wondering if I'm allowed to post multiples of threads in a day. If not, I will try to reduce the number of threads being posted.
  4. May 6, 2015 #3


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    Staff: Mentor

    Your calculation methods look fine. Remember to keep the same number of significant figures in your results as you were given as data (but retain more digits for intermediate values determined during the calculation so as to prevent rounding/truncation errors from creeping into the results).

    You can post multiple threads so long as you can manage to address them all promptly and with attention to detail; don't spread yourself so thinly that helpers become frustrated with your interactions.
  5. May 6, 2015 #4
    Please don't post multiples of the same problem.

  6. May 6, 2015 #5
    I didn't post multiples of the same problem nor I will. I'm just worrying about posting too many threads that will bother other users, because I got a lot of questions to ask from a variety of questions.
  7. May 6, 2015 #6
    No problem. Feel free to ask. That's what we other members are here for.

  8. May 6, 2015 #7
    Thanks for reply gneill :) I will always keep that in mind
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