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Homework Help: Race car velocity problem

  1. Feb 7, 2005 #1
    A race car moves such that its position fits the relationship
    x(t) = (4.4 m/s) t + (0.91 m/s^3) t^3 (yes cubed)
    where x is measured in meters and t in seconds.Approximate the instantaneous velocity at t = 2.6 s, using a time interval of 0.2 s. Answer
    in units of m/s.

    i am just stuck and dont even know where to start
     
  2. jcsd
  3. Feb 7, 2005 #2
    ok, the velocity is
    [tex] \frac{\Delta x} {\Delta t} [/tex]

    now the question come down to what is delta x and delta t
    hope you can come out the answer
     
  4. Feb 7, 2005 #3

    dextercioby

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    Take the time origin [itex] t_{0} [/itex] to be 0.

    Daniel.
     
  5. Feb 7, 2005 #4
    but what is Xo and X?
     
  6. Feb 7, 2005 #5

    dextercioby

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    Kay.
    [tex] x_{0}=x(t_{0})=x(0) [/tex]

    [tex] x=x(2.6) [/tex]

    Daniel.
     
  7. Feb 7, 2005 #6
    ok i got all that, but what is still confusing me is the "time interval" what do i do with that
     
  8. Feb 7, 2005 #7

    what is the time interval for???
     
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