1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

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


    User Avatar
    Science Advisor
    Homework Helper

    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:
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook