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Homework Help: Magnitude and Acceleration Problem

  1. Feb 4, 2010 #1
    1. Three astronauts, propelled by jet backpacks, push and guide a 148 kg asteroid toward a processing dock, exerting the forces shown in the figure, with F1 = 29 N, F2 = 54 N, F3 = 40 N, θ1 = 30°, and θ3 = 60°. What is the (a) magnitude and (b) angle (measured relative to the positive direction of the x axis) of the asteroid's acceleration?

    2. F=ma

    3. So I've been trying to do this problem and I can't seem to figure it out. I'm on my last attempt on my online homework so I really need some help. Here's how far I've gotten:
    Ax=((29cos30)+(54cos0)+(40cos60))/148=0.667
    Ay=((29sin30)+(54sin0)+(40sin60))/148=0.332
    sqrt0.3322+0.6672=0.748
    invertan(0.332/0.667)=26.5degrees
     
  2. jcsd
  3. Feb 4, 2010 #2

    rl.bhat

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    Whether angle θ3 =60 degrees is above or below the + x-axis?
     
  4. Feb 5, 2010 #3
    The third angle is below the x axis.
     
  5. Feb 5, 2010 #4

    rl.bhat

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    In that case
    Ay=((29sin30)+(54sin0)+(40sin60))/148=0.332
    this equation is wrong. It should be
    Ay=((29sin30)+(54sin0) - (40sin60))/148=0.332
     
  6. Feb 5, 2010 #5
    So the only thing I did wrong was not negate that part?
     
  7. Feb 5, 2010 #6

    rl.bhat

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    Yes.
     
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