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Homework Help: Spacecraft Acceleration Question

  1. Oct 4, 2008 #1
    1. The problem statement, all variables and given/known data

    On a spacecraft, two engines are turned on for 684s at a moment when the velocity of the craft has x and y components of Vox=4370 m/s and Voy = 6280 m/s. When the engines are firing, the craft undergoes a displacement that has components of x= 4.11x10^6m and y = 6.07x10^6m. Find the x and y components of the craft's acceleration.

    2. Relevant equations

    D = Vo*t + 1/2 at^2

    3. The attempt at a solution

    For X:
    4.11*10^6m = 4370m(684s) + 1/2 a(684s)^2 = 4.79m/s^2

    For Y:
    6.07*10^6m = 6280m(684s) + 1/2 a(684s)^2 = 7.56m/s^2

    The answers given are 17.6m/s^2 and 25.9m/s^2, but I am not sure why. I'd appreciate any help.
  2. jcsd
  3. Oct 4, 2008 #2


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    Staff Emeritus
    Science Advisor
    Homework Helper

    What is this "= 4.79m/s^2" all about? You're saying that

    4.11*10^6m = 4.79m/s^2

    which is false. The units don't even match.

    Just solve the equation for "a". (And forget the 4.79m/s^2 part).

    p.s. you probably know this, but the 4370m should have different units.
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