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Homework Help: Force pushes and pulls two blocks at an angle

  1. Sep 24, 2010 #1
    1. The problem statement, all variables and given/known data
    A force of 23.52 N pushes and pulls to blocks
    as shown in the figure below. The vertical
    contact surfaces between the two blocks are
    frictionless. The contact between the blocks
    and the horizontal surface has a coefficient of
    friction of 0.29.
    The acceleration of gravity is 9.8 m/s2
    What is the magnitude a of the acceleration
    of the blocks?
    Answer in units of m/s2

    2. Relevant equations
    I know its the sum of Fy=N-mg=0 => N=mg
    and the sum of Fx= -fk=max

    3. The attempt at a solution
    fk=ukN=> fk=20.4624
    but I do not know how to plug in Fcostheta or Fsintheta and I know those need to be used somewhere

    [PLAIN]http://img685.imageshack.us/img685/9849/006sl.png [Broken]
    Last edited by a moderator: May 4, 2017
  2. jcsd
  3. Sep 24, 2010 #2


    User Avatar
    Gold Member

    Create a free body diagram for each block, and then use ∑F=manet to find the resulting acceleration.

    What forces are acting on each block?
    How can you use these forces to find the net force on the blocks in the x direction?
  4. Sep 24, 2010 #3
    On the first block in the y direction there is N and m1g
    in the x direction there is fk and F...
    On the second block in the y direction there is Fsintheta, N, and m2g
    in the x direction there is fk and Fcostheta...

  5. Sep 24, 2010 #4

    Doc Al

    User Avatar

    Staff: Mentor

    The sum of the vertical components on each block must add to zero, but N and mg are not necessarily the only forces with vertical components.
    The sum of horizontal forces must equal max. What are the horizontal forces acting on this system?
  6. Sep 24, 2010 #5
    Thanks! figured out the other components!!!

    Thank you for you're help on my other problems too you're a live saver
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