Question

A stone is dropped from the top of a tower $500m$ high into a pond of water at the base of the tower. When is the splash heard at the top? Given, $g=10m{s}^2$ and speed of sound $=340m{s}^{-1})$.

Answer 1

Let the time to hear the splash be $t$ seconds

Given : Height of the tower $H=500$ m

Thus time taken by the stone to reach the bottom $t_1=\sqrt{\frac{2H}{g}}$

$t_1=\sqrt{\frac{2\times 500}{10}}=10$ s

Speed of sound $v=340$ $m{s}^{-1}$

Thus time taken by sound to reach the top $t_2=\frac{H}{v}=\frac{500}{340}=1.47$ s

$\therefore$ Total time taken to hear the sound of splash $t=t_1+t_2=10+1.47=11.47$ s