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142. Problem 20.9 (RHK) A stone is dropped into a well. The sound of the splash is heard 3.00 s later. We have to find the depth of the well. |
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Solution: Click For PDF Version Let the depth of the well be h m. As the stone is in
free-fall, its acceleration will be g. The time
The time
where
The total time
Roots of this quadratic equation are
Substituting the values, we get
The physical solution is
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taken
by the stone to reach the bottom of the well is
taken by
the sound of splash in travelling the length of the well is
is the
speed of sound in air and is taken to be
. 
is 3 s.
We thus have the equation
