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System of Objects

  1. Sep 23, 2008 #1
    System of Objects
    1. The problem statement, all variables and given/known data


    Find the acceleration of the system of two masses shown in the figure, given that m1 = 10 kg, m2 = 20 kg, θ = 60o and φ = 30o. Assume that the incline plane is smooth (i.e., there is no friction) and that g = 10 m/s2.


    2. Relevant equations
    A: T=m[tex]_{2}[/tex]g*sinθ + m[tex]_{1}[/tex]g*sinφ
    B: T[tex]_{1}[/tex]=T[tex]_{2}[/tex]
    C: F=ma

    3. The attempt at a solution
    T[tex]_{total}[/tex]=223.2 using A
    -----
    F=m[tex]_{2}[/tex]g*sinθ - m[tex]_{1}[/tex]g*sinφ

    F=123.21
    -----
    Using C: a=F/m
    a=m[tex]_{2}[/tex]g*sinθ - m[tex]_{1}[/tex]g*sinφ / m[tex]_{1}[/tex] + m[tex]_{2}[/tex]
    a= 4.11m/s[tex]^{2}[/tex]



    I'm not sure how to approach this one....
    I know tension = T[tex]_{1}[/tex]=T[tex]_{2}[/tex]...
    Then i get the Force that will be going right since m[tex]_{1}[/tex] < m[tex]_{2}[/tex]
    and find the acceleration. I just want someone to see if I understood this right.
    I was trying to approach the masses as two different components, but it didn't work that well..
     

    Attached Files:

  2. jcsd
  3. Sep 24, 2008 #2

    Doc Al

    User Avatar

    Staff: Mentor

    Where did you get this equation?
    These make sense.

    Do this: Draw a free body diagram for each mass, showing all forces acting. Then apply Newton's 2nd law (your equation C) to each mass. Combine the two equations to solve for the acceleration.
     
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