(a) The amount of sound energy passing each second through unit area.
(b) (i) Time interval between the original sound and the reflected sound must be 0.1 s.
(ii) The minimum distance of obstacle from the source sound must be 17 m.
(c) Given, h = 44.1 m,
u = 0,
g = 9.8 m s^-2
Using the equation S = ut + 1/2 at^2, we have
t^2 = (44.1x2) /9.8 = 44.1 / 4.9 = 9
or t = 3 second
Time taken by sound to reach height = 3.13 - 3 = 0.13 s
Hence, V = d/t = 44.1/0.13 = 339.2 ms^-1