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Homework Help: Acceleration as a Function of Velocity

  1. Feb 8, 2010 #1
    1. The problem statement, all variables and given/known data

    When 2<=t<=6
    v= 4/a in ft/sec2

    v= 6 ft/sec @ t=2s

    Find a at t=3s


    2. Relevant equations

    a=dv/dt.

    3. The attempt at a solution

    My integration is horribly wrong and honestly not worth typing. LOL
     
  2. jcsd
  3. Feb 8, 2010 #2
    You write,

    v= 4/a in ft/sec^2

    something is goofy here, something is not right?
     
  4. Feb 8, 2010 #3
    I'm sorry....acceleration (a) should be in ft/sec^2

    so a=4v^-1
     
  5. Feb 8, 2010 #4
    Now you have acceleration = 4/velocity what are the units of the 4

    acceleration * time has units of velocity. Your expression a=4v^-1 still confuses me. Does the number 4 have units? I'm missing something that others might be missing as well.
     
  6. Feb 8, 2010 #5
    No units on 4 it's just a constant?

    the original problem is v = 4 divided by acceleration or v = 4/a

    I solved for acceleration (a hint by my professor) so acceleration = 4 divided by velocity or a = 4/v
     
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