A girls hears an echo of her own voice from a distant tall building after $2 s$ . What is the distance of the girl from the building ? (Speed of sound in air= $344 m / s$ )

Open in App

Solution

Let distance of girl from building be $d$
Speed of sound = $v = 344 m / s$
Distance travelled by sound from girl to building is $d$ and distance travelled by echo from building to girl is also $d$ .
So total distance travelled= $2 d$
Time taken $t = 2 s$
$S p e e d = \frac{D i s t a n c e}{T i m e}$
$v = \frac{2 d}{t}$
$2 d = v t$
$2 d = 344 \times 2$
$2 d = 688 m$
$d = 344 m$

Suggest Corrections

Similar questions

Q. A road runs midway between two parallel rows of buildings. A motorist moving with a speed of

36 k m h^{- 1}

sounds the horn. He hears the first echo one second after he has sounded the horn. Speed of sound in air is

330 m s^{- 1}

. Then The distance between the two buildings and the time after which he hears second echo are

Q. A 2 m tall girl is standing at some distance from a building of height 20 m. The angle of elevation from her eyes to the top of the building increases from 45º to 60º as she walks towards the building. Then, the distance between the initial position and the final position of the girl is

(\sqrt{3} = 1.732)

(a) What is an echo? How is echo formed?

(b) What is the minimum distance in air required from a sound reflecting surface to hear an echo (at $20^{o}$ C)?

(c) A man standing 825 metres away from a cliff (steep rock) fires a gun. After how long will he hear its echo? The speed of sound in air is $330 m / s$ .

Join BYJU'S Learning Program

A girls hears an echo of her own voice from a distant tall building after 2s . What is the distance of the girl from the building ? (Speed of sound in air=344m/s)

Let distance of girl from building be dSpeed of sound = v=344m/sDistance travelled by sound from girl to building is d and distance travelled by echo from building to girl is also d.So total distance travelled=2dTime taken t=2sSpeed=DistanceTimev=2dt2d=vt2d=344×22d=688md=344m

A girls hears an echo of her own voice from a distant tall building after $2 s$ . What is the distance of the girl from the building ? (Speed of sound in air= $344 m / s$ )