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Homework Help: Newton third law

  1. Oct 30, 2007 #1
    a box of books weighing 325N moves with a constant velocity across the floor when it is pushed with a force of 425N exerted downward at an angle of 35.2 degree below the horizontal . find the coefficient of kinetic friction between the box and the floor.

    what i do :please see check it

    the coefficientof kinetic friction equal to the force of kinetic divided by the normal force = 425-425xcos35.2 / 325+425xsin35.2 = 0.136
  2. jcsd
  3. Oct 30, 2007 #2


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    Homework Helper

    Yes. You are right.
  4. Oct 30, 2007 #3
    are u sure ?
  5. Oct 30, 2007 #4


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    Staff Emeritus
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    Where does the first 425 come from on the numerator? What much the frictional force be equal to?
  6. Oct 30, 2007 #5


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    Homework Helper

    Yes.You are right,Cristo. Only 425cos35.2. Sorry.
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