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Question on drag

  1. Aug 10, 2006 #1
    If the force of drag is proportional to the velocity, then:
    [tex] F_d = -kv [/tex]
    However, the units of k are very strange. Does this mean that the model is completely wrong?
     
  2. jcsd
  3. Aug 10, 2006 #2

    ZapperZ

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    What do you mean by "strange"? What did you expect the units of "k" supposed to be?

    Note that just because something is a constant, doesn't mean it doesn't have any units, or that it must have only certain types of units.

    Zz.
     
  4. Aug 10, 2006 #3
    By strange, I mean kg/s. Which seems strange in the idea of projectiles or falling objects (in rocket motion it would make much more sense).
     
  5. Aug 10, 2006 #4

    ZapperZ

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    I still don't see why it is strange. Why does having the unit of kg/s for the constant seem strange? It is, after all, connecting a "force" (which has a mass dependence), to a velocity (which has a time rate of change dependence).

    Sounds perfectly un-strange to me.

    Zz.
     
  6. Aug 10, 2006 #5

    Hootenanny

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    Would you consider it strange if we quoted the value of a force as 5 kg.m.s-2?
     
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