2. Amit, Emad, and Joshua are holding a tuning fork oscillating at 256 Hz. They walk towards a wall at a constant speed of 1.33 m/s. Use v = 344 m /s for the speed of sound. a) What is the apparent frequency that they hear (reflected from the wall)? (5 pts) b ) What beat frequency do they observe between the tuning fork and its echo? (5 pts) C) How fast must they walk away from the wall to observe a beat frequency of 5 Hz? (5 pts)