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Homework Help: Acceleration by force

  1. Nov 20, 2008 #1
    1. The problem statement, all variables and given/known data

    The instruments attached to a weather balloon in the figure below have a mass(m) of 4.8 kg. The balloon is released and exerts an upward force(F) of 109 N on the instruments. What is the acceleration of the balloon and instruments?

    2. Relevant equations

    F = ma

    3. The attempt at a solution

    F = ma
    109N = (4.8 kg)(a)
    a = 109N / 4.8kg
    a = 22.7 m/s^2

    I got this answer, but its not the right answer.
  2. jcsd
  3. Nov 20, 2008 #2


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    Homework Helper
    Gold Member

    Remember that it is the sum of the forces that equals ma. You have not added up all the forces. There is one very important force that you have forgot about. What else is pulling on the system?
  4. Nov 20, 2008 #3
    oh right, i got it. thank you
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