Discuss the below:
Q: A French submarine and a U.S. submarine move toward each other during maneuvers in motionless water in the North Atlantic. The French sub moves at 50.0 km/h, and the U.S. sub at 70.0 km/h. The French sub sends out a sonar signal (sound wave in water) at 1000 Hz. Sonar waves travel at 5470 km/h. a) What is the signal's frequency as detected by the U.S. sub? b) What frequency is detected by the French sub in the signal reflected back to it by the U.S. sub?