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Homework Help: Two Beams

  1. Apr 12, 2004 #1
    Two identical uniform beams, each having a mass of 4 kg, are symmetrically set up against each other on a floor with which they have a coefficient of static friction µ = 0.609 .

    a) What is the minimum angle the beams can make with the floor without falling?
    b) For the angle calculated in part (a), what is the magnitude of the force exerted on one beam by the other beam, at the apex?

    Next a heavy point mass 1.2 kg is balanced on the apex.
    c) What is the normal force exerted on each beam by the floor?
    d) For this case, what is the minimum angle the beams can make with the floor without sliding?

    Thanks for the help in advance...see the attached picture for what the problem looks like.

    Attached Files:

  2. jcsd
  3. Apr 12, 2004 #2
    I'm having problems with this same problem too. This is what the help says for the first two parts...

    HELP: Draw a FBD and make sure all forces and torques sum to zero.
    HELP: Your FBD should show 4 different forces on each beam. A convenient point about which to calculate the torque for one beam is the point where the beam rests on the ground.

    HELP: Consult your FBD and examine the horizontal forces.

    I tried and I think the four forces are acting on each beam are the (weigh, normal, force of friction, and the force from the opposing beam). Can someone help out?
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