Question 779503
A rock is dropped into an abandoned mine and a splash is heard 9 s later. Assuming that it takes a negligible time for the sound to travel up the mine shaft, determine the depth of the shaft and how fast the rock was falling when it hit the water.
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s = at^2/2 = 4.9t^2/2
s = 198.45 meters deep
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v = at = 9.8*9
v = 88.2 meters/sec at impact