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Pushing a box (friction)

  1. Oct 16, 2009 #1
    1. The problem statement, all variables and given/known data

    A stockroom worker pushes a box with mass 11.1 kg on a horizontal surface with a constant speed of 3.80 m/s. The coefficient of kinetic friction between the box and the surface is 0.170.


    2. Relevant equations
    F=ma
    w=mg


    What horizontal force must be applied by the worker to maintain the motion?

    I found that the Fapplied is 18.5N


    If the force calculated in part A is removed, how far does the box slide before coming to rest?

    This question I'm having problems on. Here is what I did

    18.5N = 11.1kga

    a=1.66666667 m/s^2

    Then I used the equation of

    Vfinal^2=Vinitial^2+2a[tex]\Delta[/tex]x

    [tex]\Delta[/tex]x = 0 - 14.44m/s
    --------------
    2(1.66666667)


    [tex]\Delta[/tex]x=4.3m ?
     
  2. jcsd
  3. Oct 16, 2009 #2

    rock.freak667

    User Avatar
    Homework Helper

    Yes that is correct.

    Also you could have used conservation of energy.

    Note that your a=1.66666667 m/s2 should really be a=-1.66666667 m/s2

    But I believe you put it as negative while working it out, so just remember to write the - sign else your teacher might give you it wrong.
     
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