Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Friction, Statics, Finding maximum angle and minimum coefficient of friction

  1. Nov 22, 2011 #1
    1. The problem statement, all variables and given/known data
    If the coefficient of static friction at B is μs = 0.3, determine the largest angle
    θ, and the minimum coefficient of static friction at A, so that the roller remains self-
    locking, regardless of the magnitude of the force P applied to the belt. Neglect the weight
    of the roller and neglect friction between belt and vertical surface.

    2. Relevant equations

    3. The attempt at a solution
    I have attempted the solution quite a few times a couple of different ways. I keep getting stuck with variables that I can't solve for, so I have come to the conclusion that I am probably not going about it the right way. My first attempt, I took the moment about A, and then summed up the forces in the x and y directions, but wound up not being able to solve for θ or μA. I attached an attempt at a free body diagram, perhaps I don't have the friction forces going in the right direction? I would appreciate any help!

    Attached Files:

    • FBD.gif
      File size:
      7.4 KB
  2. jcsd
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook

Can you offer guidance or do you also need help?