Question

A SONAR (sound navigation and ranging) uses ultrasonic waves to detect and locate objects underwater. In a submarine equipped with a SONAR the time delay between generation of a probe wave and the reception of its echo after reflection 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 m s⁻¹).

Answer 1

Distance = speed×time
D = 1450×77/2 (because sound also comes back after deflection)
Distance = 55825m = 55.82km

Answer 2

Hey buddy,

# Answer- 55.82 km.

# Explaination-
Let the distance between the ship and the enemy submarine be ‘S’.
Speed of sound in water = 1450 m/s

Time lag between transmission and reception of Sonar waves = 77s

In this time lag, sound waves travel a distance which is twice the distance between the ship and the submarine(2S).

Time taken for the sound to reach the submarine = 77/2 = 38.5s

∴ Distance between the ship and the submarine
S = 1450×38.5
S = 55825m
S = 55.82 km.

Hope this helps you...