A train is traveling at 30.0 relative to the ground in still air. The frequency of the note emitted by the train whistle is 262 . The speed of sound in air should be taken as 344 . What frequency is heard by a passenger on a train moving at a speed of 18.0 relative to the ground in a direction opposite to the first train and approaching it? Express your answer in hertz. What frequency is heard by a passenger on a train moving at a speed of 18.0 relative to the ground in a direction opposite to the first train and receding from it? Express your answer in hertz.