Question

Submarine a travels horizontally at 11.0 m/s through ocean water. it emits a sonar signal of frequency f 5 5.27 3 103 hz in the forward direction. submarine b is in front of submarine a and traveling at 3.00 m/s relative to the water in the same direction as submarine
a. a crewman in submarine b uses his equipment to detect the sound waves ("pings") from submarine
a. we wish to determine what is heard by the crewman in submarine
b. (a) an observer on which submarine detects a frequency f 9 as described by equation 17.19? (b) in equation 17.19, should the sign of vs be positive or negative? (c) in equation 17.19, should the sign of vo be positive or negative? (d) in equation 17.19, what speed of sound should be used? (e) find the frequency of the sound detected by the crewman on submarine b

Answer 1

Velocity of submarine A is vs = 11.0m/s
frequency emitted by submarine A. F = 55.273 × 10∧3HZ
Velocity of submarine B = vO = 3.00m/s
The given equation is
f' = ((V + vO) ((v - vS)) × f
The observer on submarine detects the frequency f'.
The sign of vO should be positive as the observer of submarine B is moving away from the source of submarine A.
The speed of the sound used in seawater is 1533m/s
The frequency which is detected by submarine B is 
fo = fs (V -vO/ v +vs)
= 53.273 × 10∧3hz) ((1533 m/s - 4.5 m/s)/ (1533 m/s +11 m/s)
fo = 5408 HZ