Problem 3: Whistling footballs: Two students standing 54.9m apart are tossing around footballs designed to whistle while they are airborne. (a) When student A throws her football toward student B at 16.0 m/s, it emits a frequency of 680 Hz. What frequency is heard by student B? (b) When student B throws his football toward student A at 15.0 m/s, it emits a frequency 670 Hz. What frequency is heard by student A