4. Us A clever physics student is attempting to use the Doppler Effect to measure their speed as they walk down a hallway that is closed at its far end. They hold a tuning fork that oscillates at 256 Hz , and as they walk with a constant speed towards the end of the hallway they observe a beat frequency of 2.00 beats/s.

a. What frequency is the student hearing from the sound reflected by the wall at the end of the hallway? Explain your conclusion.

b. Calculate the speed at which the student moves. Explain your work.