Question

A stone is dropped into a well 44.1 m deep. The sound of splash is heard 0.13 seconds after the stone hits the water. What should be the velocity of sound in air?

• A. 319 m/s
• B. 339 m/s
• C. 359 m/s
• D. 369 m/s

Answer 1

The correct option is B 339 m/s

The time taken for sound to come back to the observer consists of the time of fall of the stone and the sound to travel up the well, therefore
$t=\sqrt{\frac{2h}{g}}+\frac{h}{v}$
$t=\frac{44.1}{V}\Rightarrow 0.13=\frac{44.1}{V}$
$\Rightarrow V=\frac{44.1}{0.13}=339.28m/s$