in a suspense thriller movie, two submarines X and Y approach each other, traveling at 11.5m/s and 18.9m/s, respectively. Submarine X pings submarine Y by sending a sonar wave of frequency 2190Hz. Assume that the sound travels at 1550m/s. suppose the submarines barely miss each other and begin to move away from each other. what frequency does submarine Y detect from the pings sent by X?