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Homework Help: Constant Velocity

  1. Dec 19, 2003 #1
    How do I use Kinematic equation with constant velocity.
    I only have used with intital and final velocity.



    A parachute dropped from a 30-meter-high cliff falls with a constant
    velocity of 1.5 meters per second. Twenty-two seconds later a stone is
    dropped from the cliff.

    a. How long does it take the parachute to hit the ground?


    b. How long does it take the stone to hit the ground?
    I solved this using d=v_i * t + 1/2 * a *t ^2

    24.5 seconds
     
  2. jcsd
  3. Dec 19, 2003 #2

    Doc Al

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    Staff: Mentor

    You can use the exact same equation by setting a=0. It simplifies to d = v*t ... I hope that equation looks familiar!
     
  4. Dec 19, 2003 #3
    d=v*t+1/2*a*[tex]t^2[/tex]

    -30m = (-1.5m/s)*t + 0.5 (0m/s)*[tex]t^2[/tex]

    I come up with t=20s

    Am I going in the right direction?
     
  5. Dec 19, 2003 #4
    yes, if the velocity remains contant
    then a=0
     
  6. Dec 19, 2003 #5

    Doc Al

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    Staff: Mentor

    Perfect.
     
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