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Homework Help: Time Equation Help Needed

  1. Dec 16, 2009 #1
    Hi All - I am trying to find an equation that gives the time as a function of initial velocity, distance traveled, and specified acceleration. That is, t = some function of v(0), d, and a.

    We ran a simulation problem for distances 25 and 50 meters and my times were - 4.099 and 6.141 respectively for initial velocity of 2.00 and inital acceleration of 2.00. i can't come up with any equations that fit my data. any input please?????

    Thank you!
    Ashley
     
  2. jcsd
  3. Dec 17, 2009 #2

    Doc Al

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    Staff: Mentor

    Last edited by a moderator: Apr 24, 2017
  4. Dec 17, 2009 #3
    So would it be:
    t=SQRT(2s-v(o)/a

    s=distance
    v(o)=inital velocity

    I've tried this but it doesn't give me the exact anser - is it ok to round up or down? Initally I found final velocity and then plugged it in but the challenge is to use one equation. Input?

    Thank you!
     
  5. Dec 17, 2009 #4

    Doc Al

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    The starting equation would be:
    s = v0t + 1/2at2

    To find t you'll need to solve the quadratic.
     
  6. Dec 17, 2009 #5
    Thank you for this tip. I am not very "up" on my physics - this is my first introduction to it on a college level. What are the rules for solving for the quadratic? Does that involve derivitives? Thank you!
     
  7. Dec 17, 2009 #6

    Doc Al

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    No need for calculus, just the 'quadratic formula'. (Google it!)

    Note that I am assuming that your setup is one where the acceleration is constant. (You didn't actually state that.)
     
  8. Dec 17, 2009 #7
     
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