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Stoned Parachute Problem

  1. Oct 10, 2006 #1
    A. A small parachute dropped from a 58-m-high cliff falls with a constant velocity of 1.2m/s. 43s after the parachute is dropped, a stone is dropped from the cliff. will the stone catch up with the parachute before it reaches the ground? yes or no?

    B. how long would it take for the parachute to reach the ground if it didn't get hit by the stone?

    C. How long would it take the stone to hit the ground if there were no interference from the parachute?

    Solutions I have tried:

    A. For this I need to know B & C and I know that c needs to be less than 5 seconds

    B. For this I take the equation 1.2m/s = 58/t and i solve for t my answer is 48.3333

    C. For this I know initial velocity is 0 I'm not sure about the final velocity acceleration is -9.8 and t is my unknown but I don't understand how to find it since I do not have my final velocity.

    Would this Work final velocity= square root of initial velocity squared+2a*d and the answer would be 33.71646482 then i would use final velocity= initial velocity+ a*t the answer would be 3.440455594s so since this is less than 5s the answer to A would be yes ? Is this correct?
  2. jcsd
  3. Oct 10, 2006 #2

    Doc Al

    User Avatar

    Staff: Mentor

    You don't need to be given the final velocity--you have the distance.

    Absolutely correct!

    But you could also do it with less work by using a different kinematic equation--one that relates distance, time, and acceleration.
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