Two physicists-runners, Albert and Isaac, practice in the woods and also perform various experiments with sound frequencies and test the Doppler eect. Both runners have sound generators of the frequency 180 Hz and the receivers which measure the frequency of received waves. Assume that the speed of sound in the air is 350 m/s.
a) In the rst experiment Isaac stays at rest and receives the sound waves from Albert who is running away from him. If the frequency of received waves by Isaac is 175 Hz what is Albert's speed?
b) Isaac tries to catch Albert and runs behind him. Albert is still running away from him. How does the received frequency received by Isaac change if Isaac's speed is 1/2 of Albert's speed?
c) What is the frequency Isaac would receive if Albert stops running while Isaac is still trying to catch him with the same speed as before? Neglect any momentary delay of the travel time of the waves.