A stone is dropped from the top of a tower 500 m high into a pond of water at the base of the tower. When is the splash heard at the top?

Let the time to hear the splash be t seconds
Given : Height of the tower H=500m
Thus time taken by the stone to reach the bottom t1=√(2H/g)
t1=√(2 × 500/10) = 10s
Speed of sound v=340ms⁻¹;
Thus time taken by sound to reach the top t2=H/v = 500/340 = 1.47s
∴Total time taken to hear the sound of splasht = t1 + t2 = 10 + 1.47 = 11.47s