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Homework Help: Calculating Tension

  1. Nov 17, 2008 #1
    1. The problem statement, all variables and given/known data
    http://img293.imageshack.us/img293/1212/47236686fi5.png [Broken]

    I have to find the acceleration (magnitude and direction)
    Tension in T1, and T2

    2. Relevant equations
    a = F/m P = F/A Fg = mg

    3. The attempt at a solution
    Well, i figured out the acceleration, by finding the difference in Fg between the two sides, and dividing that by the mass. I get .75m/s^2. Using that, I can get that the net force is 7kgx.75m/s^2 = 5.25N

    I don't know how to get from there to the tension, mostly b/c the forces are changed by gravity, and tension is affected by gravity.
    Last edited by a moderator: May 3, 2017
  2. jcsd
  3. Nov 17, 2008 #2


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    Hi FOX2PRO,

    Draw a free body diagram for the 4kg mass. What does that give?
  4. Nov 17, 2008 #3
    Well, theres the force of gravity 4kg(9.8), and the net force, 5.25N
    So, they are at opposite ends, so the tension would be 36.2N?
  5. Nov 17, 2008 #4


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    Gravity is pulling down on the 4kg block, but what force is pulling up on the 4kg block?

    Then, since you know the acceleration of the 4kg block you can solve for T1.
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