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Homework Help: 1-D Kinematics Problem

  1. Feb 25, 2008 #1
    1. The problem statement, all variables and given/known data

    Thelma and Louise's car falls off the edge of the Grand Canyon and plunges to certain catastrophe below. The depth of the canyon at this point is 500 m. (Assume it drops off)

    A) How long will it take the vehicle to impact the canyone bottom?

    B) What will the vertical impact velocity be? Do you think they will survive, even with air bags?

    2. Relevant equations

    d = vit + 1/2at^2

    d = (vi+vf)t

    3. The attempt at a solution

    d - 500m
    ag = -9.81 m/s^2
    vi = 0m/s
    t =?

    Since you cant solve for t, i solved for Vf.

    Would the Vf be a negative number?

    Then, i pluged the vi and vf into the 2nd equatioon above, but the answer i got was different from the answer given.
  2. jcsd
  3. Feb 25, 2008 #2
    Why can't you solve for t?
  4. Feb 25, 2008 #3
    o wait, maybe i made a mistake.
  5. Feb 25, 2008 #4
    I forgot that my Vi = 0 m/s therfore does not equate to a quadratic.
  6. Feb 25, 2008 #5
    Well, use the first equation you wrote to solve for t. You know all the information you need to solve for part a.

    The D = -500 m a = -g t=? and vi= 0 The reason why I say there is no initial velocity is because once the car goes over the edge and starts to fall, it's in free fall. The car may have HORIZONTAL velocity, but there is no initial vertical velocity.

    Use that information and you can solve for v final.
  7. Feb 25, 2008 #6
    Even if it's quadratic, why wouldn't you be able to solve for t?
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