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Finding acceleration when there is friction and force is applied at an angle to horizontal

  1. Oct 5, 2014 #1
    1. The problem statement, all variables and given/known data
    Sheldon moves a box of comic books to stuarts comic book store by attaching a rope to the box and pulling with a force of 90 N at an angle of 30. The box of comic books has a mass of 20 kg and the coefficient of kinetic friction between the bottom of the box and the sidewalk is .5. Find the acceleration of the box

    2. Relevant equations
    F=ma

    3. The attempt at a solution
    i know the answer is A=.12 m/s^2 but i have no idea how to get to that answer, please explain!!
     
  2. jcsd
  3. Oct 5, 2014 #2

    phinds

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    2016 Award

    Draw the force vectors. You have not even started to solve such a problem until you have drawn the force vectors.
     
  4. Oct 5, 2014 #3
    i did i drew a fbd
     
  5. Oct 5, 2014 #4
    and i think its Facos(30) for x axis and Fasin(30) for y axis
     
  6. Oct 5, 2014 #5

    phinds

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    I say again, draw the force vector diagram (and show it here).
     
  7. Oct 5, 2014 #6
    I actually just figured it out!! :) but thanks for your help anyways!!
     
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