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If Kinetic friction is a constant can I accelerate forever?

  1. Oct 3, 2009 #1
    If a limiting friction of an object is 10N and the kinetic friction is 5 N.

    If I apply a force of 20 N continuosly would I be accelerating with a 5 N force forever.
  2. jcsd
  3. Oct 3, 2009 #2


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    Hi sameeralord! :smile:

    (limiting friction is the maximum value of static friction)

    No … you would be accelerating with a 10 N force forever …

    once the object has started moving, you can forget the static friction completely (and you can reduce the applied force).

    So if you apply a force of 6 N continuously, you will be accelerating with a 1 N force forever. :wink:
  4. Oct 3, 2009 #3


    Staff: Mentor

    You meant 15 N. Right?
  5. Oct 3, 2009 #4


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    Right! :smile:
  6. Oct 3, 2009 #5
    You do need more and more power to overcome friction. The heat produced will become a problem too.
  7. Oct 3, 2009 #6
    Now this is a "work" problem. Are you familiar with "work"?

    Work is a measurement of energy, and is equal to force X distance.

    In this case, 15N (the force of friction) times the distance the object slides = the heat energy given off (in "joules").

    So, when the object is moving faster, it covers more distance per unit time, so it also generates more heat per unit time.
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