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Coefficient of static friction

  1. Nov 29, 2005 #1
    An apple crate with weight of 49N accelerates at 0.5m/s2 along a horizontal a force of 20N apllied above the horizontal at 19 degrees is required to bring the crate on the verge of motion. Find the coefficient of static friction between the crate and the surface.

    -usn+20 cos 19 x direction
    N+W+20 cos 19 y direction

    F=ma F=5x0.5
    F=2.5

    don't know what to do next..please help
     
  2. jcsd
  3. Nov 29, 2005 #2

    mrjeffy321

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  4. Nov 29, 2005 #3
    I did it exactly the way I did the other problem but according to the book the answer should be 0.445 but Im getting 0.386
     
  5. Nov 29, 2005 #4
    i dont know what im doing wrong I dont thnik the book is wrong it says 0.445 and I got 0.386 like 4 times in a row
     
  6. Nov 29, 2005 #5

    mrjeffy321

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    I got .386 too. But that is not to say that I didnt do anything wrong either, but it is a good sign we both got the same answer.
     
  7. Nov 30, 2005 #6
    I redid the question and I got 0.445 I forgot to set fx and fy equal to zero because the crate is not in motion it is on "the verge of motion"
     
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