An ultrasonic wave of frequency 45000Hz sent ot by a SONAR sows a frequency rise of 6ooHz on reflection from an aproaching submarine.If speed os sound in water is 1500m/s czlculate speed of submarine.

Open in App

Solution

f1 = f( c + Vo / c)
frequency heard by the submarine = f1
f= 45000Hz
c= speed of sound in water = 1500m/s
Vo = velocity of submarine
f1 = 45000( 1500 + Vo)/ 1500 = 30 (1500 + Vo)
Now the frequency heard again at SONAR = 45000 + 600 = 45600 Hz = f2
f2 = f1 ( c/ c- Vo) = 30 (1500 + Vo) ( 1500 / 1500- Vo) = 45600 ..........(1)
solving the above equation we get
1500 + Vo = 1.013 (1500- Vo)
2.013 Vo = 20
Vo = 9.935 m/sec

Suggest Corrections

Similar questions

Q. A SONAR system fixed in submarine operates at a frequency of 40.0 kHz. An enemy submarine moves towards the SONAR with a speed of

360 k m h^{- 1}

Taking the speed of sound in water as

1450 m s^{- 1}

, then frequency of the reflected sounds is

Two submarines are approaching each other in a calm sea. The first submarine travels at a speed of 36 km $h^{- 1}$ and the other at 54 km $h^{- 1}$ ' relative to the water. The first submarine sends a sound signal (sound waves in water are also called sonar) at a frequency of 2000 Hz. (a) At what frequency is this signal received by the second submarine ? (b) The signal is reflected from the second submarine. At what frequency is this signal received by the first submarine. Take the speed of the sound wave in water to be $1500 m s^{- 1}$

Q. A SONAR inside the sea works at 40 kHz. A submarine is approaching it with a velocity 360 Km

h^{- 1}

. If the speed of sound in water is 1450 m

s^{- 1}

then the apparent frequency of waves after reflection from submarine will be

Q. A SONAR (sound navigation and ranging) uses ultrasonic waves to detect and locate objects under water. 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}

Join BYJU'S Learning Program