Question

A stone is dropped from a 500 m tall building into a pond. When is sound of splash heard after the dropping of the stone? g = 10 $m/s^2$, speed of sound = 340 m/s

• A. 10 s
• B. 1.47 s
• C. 11.47 s
• D. immediately (at t = 0)

Answer 1

The correct option is C

11.47 s

Sound needs time to reach places, let time required by stone to reach the pond be to

$S=ut+a{t}_2$

$-500=-\frac{1}{2}\times 10\times t_1^2$

$t_1=10s$

time taken by sound to reach the top =$\frac{distance}{speed}$

$t_2=1.47s$

total time after which splash is heard =$t_1+t_2$

= 10 + 1.47 = 11.47 s