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Homework Help: Constant acceleration question

  1. Sep 22, 2007 #1
    1. The problem statement, all variables and given/known data
    An interstlear ship has a mass of 8.97 kg x10^6 and is initially at rest to a star system. What constant acceleration is needed to bring the ship up to a speed of 0.51C, relative to the star system in three days.

    2. Relevant equations

    constant acceleration = v2-v1/t2-t1

    3. The attempt at a solution

    a=1.5x10^7/1.3 x 10^5
    a=120 m/s^2


    Last edited: Sep 22, 2007
  2. jcsd
  3. Sep 22, 2007 #2


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    Can you show how you got the numbers you used?
  4. Sep 22, 2007 #3
    Constant acceleration numbers...

    the numbers I used were:

    Time is 3 days (posted in question)=36 hours=2160 minutes = 129 600 or 1.3 x 10^5
    Speed is .051c (c=3.0 x 10^8) .051 x 3.0 = 1.5 x10 ^7

    I'm not sure if this is the correct way to be approaching this question? Any help would be greatly appreciated=)
  5. Sep 22, 2007 #4
    Done right, but with a lot of mistakes. Check your math:

    3 days =/= 36 hours.
  6. Sep 22, 2007 #5


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    OK, in your original post you have it as 0.51c so I didn't get the same number. Also, there are 24 hrs in a day, not 12. So it would be 72 hrs for 3 days.
  7. Sep 22, 2007 #6
    Oops, I've been doing this way to long...thanks for pointing that out, I think my brain is turning to mush! I'll try again, thanks for your help!!
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