Question

A stone dropped from the top of a tower of height 300 m high splashes into the water of a pond near the base of the tower. When is the splash heard at the top given that the speed of sound in air is 340 m $s^{-1}$? (g=9.8 m $s^{-2}$)

Answer 1

Time taken by stone to reach sound

$s=ut+\frac{1}{2}a{t}^2$

$300=0\times t+\frac{1}{2}\times 9.8\times t^2$

$=\sqrt{\frac{600}{9.8}}=7.82\sec$

Now time taken by sound to reach top of tower

$=t=\frac{d}{v}=\frac{300}{340}=0.882$

Total time taken$:-$

$=7.82+0.88=8.70\sec .$

We get, $t=8.70\sec .$