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Homework Help: Physics pulley question help please

  1. Apr 12, 2010 #1
    Diagram kkk.jpg

    1. The problem statement, all variables and given/known data
    Consider the two body system above. There is a 0.25kg object accelerating across a rough surface. The sliding object is attached by a string to a 0.1kg object which is suspended over a pulley. the coefficient of kinetic friction is 0.183. Calculate the acceleration of the block and the tension in the string.

    2. Relevant equations
    Fg=mg
    Fnet=ma


    3. The attempt at a solution

    i got the acceleration to be 1.5...m/s^2 i dont know if it is right

    fn=fg=mg 0.25 x9.81m/s^2 =2.4525N
    ff=ufn
    ff=0.183 x 2.4525N =0.4488075 ff=fg since fn=fg

    fg2= 0.1 x 9.81 =0.981 then subtracted them to get fnet then divided
     
  2. jcsd
  3. Apr 12, 2010 #2
    Let the driving force (weight of the hanging block-friction of the block on the surface)=the combined mass time acceleration. To solve for a.

    mg-Mgu=(m+M)a.

    The tension in the string should be the force required to drive the block on the surface against friction at a.

    T=Ma+Mgu.



    *or so I think, it's been a while since I have done such problems.
     
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