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Homework Help: 2-D Motion Problem with 2 masses attached by a string.

  1. Jul 23, 2015 #1


    1. The problem statement, all variables and given/known data

    Two blocks of masses m1 = 3.7 kg and m2 = 3.3 kg are connected by a string as shown in the figure above. The horizontal surface is frictionless. A 15 N force directed at 18 degrees above the horizontal acts on m2.
    Determine the acceleration of the blocks and the tension in the string.
    2. Relevant equations
    F= 15N
    3. The attempt at a solution

    Wm2= 9.8m/s^2x3.3kg = 32.34N

    ∑Fx= m⋅ax

    -Fx+M1 =m⋅ax
    -(cos 18°⋅15N)+M1 = 3.3kg⋅-ax
    -14.26N+M2 =3.3kg⋅-ax
    ax+M1 =4.321 m/s2


    +Fy+FN -Wm2 =m⋅ay

    I'm kind of stuck after this..
  2. jcsd
  3. Jul 23, 2015 #2
    Where's your FBD for mass m1?

    Your nomenclature is kind of confusing. You use M1 for the tension force and there is also an m1 mass. Then you switch back and forth between M1 and M2 which I assume is just a typo.
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