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Homework Help: Rope tension no friction question

  1. Dec 9, 2009 #1
    1. The problem statement, all variables and given/known data
    How much tension must a rope withstand if it is used to accelerate a 1050kg car horizontally at 1.20 m/s2? IGNORE FRICTION!



    3. The attempt at a solution
    What i did was
    T-Fg=ma
    T-mg=ma
    T-1050(9.8)=1050(1.20)
    T-10290=1260
    T=1.15x10 to the power of 4
    But thats not the answer the answer is 1.26x to the power of 3kg
    What did i do wrong?
     
  2. jcsd
  3. Dec 9, 2009 #2

    ideasrule

    User Avatar
    Homework Helper

    Why are you including gravity? It's not as if you're lifting the car up.

    Try drawing a free-body diagram and writing out Newton's second law TWICE, once for the y direction and once for the x direction.
     
  4. Dec 9, 2009 #3
    Sorry i made a dumb mistake!
    its been a long day and i was for some reason including gravity in alot of things that i shouldn't
    i got the question now.
    thanks for replying anyways:)
     
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