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Homework Help: Tension - two objects and a string

  1. Oct 20, 2009 #1
    1. The problem statement, all variables and given/known data
    An object 1 of mass 5 kg is attached to object 2 of mass 7 kg with a string. The 5 kg object is pulled up with a 67 N force - what is the tension in the string.

    2. Relevant equations

    F= ma

    3. The attempt at a solution

    Since object 1 has an external force of 67 N acting upon it, that force should be subtracted by the weight of object 1: (5)(9.8) = 49 N
    67 - 49 = 18 N

    Object 2 just has its weight force acting upon it: (7)(9.8) = 68.6 N

    I've calculated the forces acting on the objects - but I'm not sure how to calculate tension from here.
  2. jcsd
  3. Oct 20, 2009 #2


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    Homework Helper

    Find the acceleration of m1 and m2 due to applied force.
    What is the net force acting on m2?
    What is its equate it to the combined acceleration to find T.
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