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Two towers different heights -- what should Heights be so impact velocity is 3x larger

  1. Apr 16, 2016 #1
    1. The problem statement, all variables and given/known data
    (I don't remember the EXACT problem because it was in an exam I took a few days ago but it was something like: If we drop the same object off of two towers, what does the height of Tower2 need to be if we want the object to fall is a velocity 3 times greater than the object falling off of tower1?

    2. Relevant equations

    3. The attempt at a solution
    What I used was the vf^2 = vi^2 + 2ad and solved for d. (vf^2-vi^2)/2a = d and if vi = 0 then d=vf^2/2a

    so the Height of tower 2 would have to be d=(3*vf^2)/2a, right?
  2. jcsd
  3. Apr 16, 2016 #2


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    Staff: Mentor


    The question you are answering is: if the height of tower #1 is d meters, then what height does tower #2 need to be for the mass to reach triple the speed?
  4. Apr 16, 2016 #3
    yes when it hits the ground
  5. Apr 16, 2016 #4


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    Staff Emeritus
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    Homework Helper

    If vf1 is the velocity of something dropped off Tower 1, then the velocity of something dropped off Tower 2, vf2 = 3 * vf1. That's how you write triple the first speed.
  6. Apr 16, 2016 #5


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    Staff: Mentor

    So, what is the answer?
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