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Cylinders on inclines

  1. Feb 6, 2007 #1
    1. The problem statement, all variables and given/known data
    This is a sample exam problem. We have an exam coming up, and I think I better know how to do this problem(the right and quick way).

    I'm just copying and pasting the problem.

    2. Two identical metal cylinders are stacked as shown in Figure 2. The weight of each cylinder is 70 lb and the diameter of each cylinder is 3 ft. Calculate all forces acting on cylinder A.

    View attachment sample exam.bmp

    2. Relevant equations

    3. The attempt at a solution

    I do not know how to do these type of problems. The circle screws me up for some reason.

    I drew a free body diagram, and a force down on each cylinder of (W). Also, cylinder A has two forces normal to the two planes. And, cylinder B also has a force normal to the surface. They both have a force on eachother Fab.

    I think I'd try to sum the forces in the x and in the y direction.

    Fx = Facos(60) + Fbcos(45) + Facos(70)

    Fy = Facos(30) + Fbcos(45) + Facos(20) + 70?

    I'm not sure if this is even right, nor am I sure what I would do next. I don't understand how to incorporate the diameter either.
  2. jcsd
  3. Feb 7, 2007 #2


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    Homework Helper

    The forces acting on cylinder A are two reaction forces from the 'ground' (i.e. normal forces), the force of gravity, and the reaction force from cylinder B. Once you have identified and named these, the rest shouldn't be a problem.
  4. Feb 7, 2007 #3
    Edit:read your work wrong.

    Look at both FBD of A and B seperately
    Last edited: Feb 7, 2007
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