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Falling object: time before it reaches the ground and its position

  1. Nov 27, 2009 #1
    A flowerpot is knocked off a balcony 20.0m above the sidewalk and falls toward an unsuspecting 1.75-m tall man who is standing below. How close to the sidewalk can the flowerpot fall before it is too lat for a warning shouted from the balcony to reach the man in time? Assume the man below requires 0.300s to respond to the warning.
    d=1/2gt2
    18.25m=4.9t2
    1.93s=t for flowerpot to fall
    v=d/t
    v=343m/s at 20C
    343=18.25/t
    t=.053s for sound to reach man
    So, tflower=tlast instant+tsound+treaction
    1.93=.053+.3+t
    1.577s=t
    okay, d=1/2gt2
    d=4.9(1.5772)
    12.2m=d


    Can someone help me i am not sure if i did it right?
     
    Last edited: Nov 27, 2009
  2. jcsd
  3. Nov 27, 2009 #2
    Re: physics

    that seems gd to me. it has fallen 12.2m so it will be 7.8m above the sidewalk
     
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