A SONAR (sound navigation and ranging) uses ultrasonic waves to detect and locate object under water. In a submarine equaipped with as SONAR, the time delay between genration of a probe wave and the recption of its echo after refection from an enemy submarine is found to be 77.0 s. What is the distance of the enemy submarine ? (speed of sound in water `= 1450 ms^(-1)`

Explanation

Here speed of sound in water `v = 1450 m s^(-1)` and time of echo `t = 77.0 s`.
If distance of enemy submarine be d, then `t =2d//v`
`:. D=vt//2=1450xx77.0//2=55825 m=55.8xx10^(3) m` or `55.8 km`.