time to fall:
h = .5 g t^2
so t = sqrt (2 g h)
time for sound to rise = h/c
5.3 = h/c + sqrt (2 g h)
sqrt (2 g h) = 5.3 - h/c
2 g h = 5.3^3 - 10.6 (h/c) + h^2/c^2
look up c at 20 deg C
and then solve the quadratic
The temperature of the air is 20.0 degrees Celsius when a tourist drops a coin into a wishing well. She hears the splash 5.30 s after drops the coin. If air resistance is ignored, how deep is the well?
3 answers
120
100