Question

Sound waves cannot travel in a vacuum. It can travel only through material medium. e.g., solids, liquids and gases. An echo is heard after 0.8 s, when a person fires a cracker 130 m from a high building:

(i) Calculate the speed of sound.

Answer 1

Step 1- Given data,

Time for echo $t=0.8seconds$
Height of building$h=132.8m$

Step 2- To find the speed of the sound wave-

Distance traveled by sound $d=2\times height$
Distance traveled $=2d=2\times 132.8=265.6m$
As the speed of sound$v=\frac{Dis\tan ce\left(2d\right)}{time\left(t\right)}$

$$\begin{gathered} \Rightarrow v=\frac{2d}{t} \\ \Rightarrow v=\frac{265.6}{0.8}=332m/s. \end{gathered}$$

Thus, the speed of the wave is $332m/s.$