A hiker determines the length of a lake by listening for the echo of her shout reflected by a cliff at the far end of the lake. She hears the echo 2.0 after shouting. Estimate the length of the lake in meters

Q:A hiker determines the length of a lake by listening for the echo of her shout reflected by a cliff at the far end of the lake. She hears the echo 2.0 after shouting. Estimate the length of the lake in meters. The speed of sound in air is 343 m/s.

Answer:

343 m.

Explanation:

Echo: This is the sound heard after the reflection of sound wave in a plane surface.

v = 2x/t ... Equation 1

Where v = speed of sound in air, x = length of the lake, t = time the echo was heard.

making x the subject of the equation,

x = vt/2 ... Equation 2

Given: v = 343 m/s, t = 2 s

Substitute into equation 2,

x = 343 (2) / 2

x = 343 m.

Hence the length of the lake in meters = 343 m.