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Homework Help: Tension in a 2 Mass System

  1. Nov 14, 2007 #1
    1. The problem statement, all variables and given/known data

    In the ideal setup showin in the following figure, M1=3.0 kg and M2=2.5KG
    A) What is the acceleration of the 2 mass system?
    B) What is the tension in the string?

    2. Relevant equations
    Asys=M2 * g - M1 * g (sin[tex]\oslash[/tex]) / M1 + M2

    3. The attempt at a solution

    Calculated the acceleration of the system using above equation and obtained:

    Asys=1.24 m/s^2

    My teacher gave me full credit on that part of my answer. On part B, however, I was expected to find the tension on the string. Here's what I attempted:
    Asys=M1(g) -T / M1
    1.24 m/s^2 = 2.5(9.8) - T / 5.5 kg

    I am thinking I need to also divide by mass 2? Either way, I think I could use a fresh approach at thinking about tension. To me, it just seems like the transferred force through a string....I guess I'm a bit confused.

    Thanks in advance,


    Attached Files:

    Last edited: Nov 14, 2007
  2. jcsd
  3. Nov 14, 2007 #2


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    Homework Helper

    Asys=M1(g) -T / M1
    1.24 m/s^2 = 2.5(9.8) - T / 5.5 kg

    1.24 m/s^2 = [2.5(9.8) - T] / 2.5 kg Try this one and find T
  4. Nov 14, 2007 #3
    Wow, tell me my mistake wasn't that simple...

    My new T= -0.127

    Thanks guys...I can't even believe I didn't see that!
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