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Homework Help: Find angle.

  1. Apr 6, 2009 #1
    1. The problem statement, all variables and given/known data
    In Figure 6-62 a fastidious worker pushes directly along the handle of a mop with a force . The handle is at an angle θ = 40° with the vertical, and μs = 0.61 and μk = 0.48 are the coefficients of static and kinetic friction between the head of the mop and the floor. Ignore the mass of the handle and assume that all the mop's mass m = 0.65 kg is in its head. (a) If the mop head moves along the floor with a constant velocity, then what is F? (b) If θ is less than a certain value θ0, then (still directed along the handle) is unable to move the mop head. Find θ0.

    Im having trouble understanding how to solve for part b.

    i got to:
    Fsin0 - Fs (mg-Fcos0)=0

    but i can't solve of the angle.
     
  2. jcsd
  3. Apr 7, 2009 #2

    tiny-tim

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    Hi intenzxboi! :smile:

    (have a theta: θ and a phi: φ :wink:)

    Hint: put Asinθ + Bcosθ in the form C(sinθcosφ + cosθsinφ), for some angle φ :smile:
     
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