A girl is sitting near the open window of a train that is moving at a velocity of 20.00 m/s to the east. The girl's uncle stands near the tracks and watches the train move away. The locomotive whistle emits sound at frequency 560.0 Hz. The air is still. (Use 343.0 m/s for the speed of sound in air for all parts of this question.

(a) What frequency does the uncle hear?

(b) What frequency does the girl hear?

(c) A wind begins to blow from the east at 20.00 m/s. What frequency does the uncle now hear?

(d) What frequency does the girl now hear?