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

AI Thread Summary
A flowerpot falling from a height of 20.0 meters takes approximately 1.93 seconds to reach the ground. The sound of a warning shout takes about 0.053 seconds to reach a man standing below, who requires 0.300 seconds to react. Calculating the total time for the flowerpot to fall and for the sound to reach the man indicates that the pot can fall 12.2 meters before it is too late for a warning. This means the flowerpot would be 7.8 meters above the sidewalk at the last moment a warning could be effective. The calculations confirm that the timing for the warning and reaction aligns with the flowerpot's descent.
ellyb
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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=dCan someone help me i am not sure if i did it right?
 
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that seems gd to me. it has fallen 12.2m so it will be 7.8m above the sidewalk
 
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