(a) In Problem 42, find the beat frequency between the outgoing and reflected sound waves.
In problem 42,
Blood flow rates can be found by measuring the Doppler shift in frequency of ultrasound reflected by red blood cells (known as angiodynography). If the speed of the red blood cells is v, the speed of sound in blood is u, the ultrasound source emits waves of frequency f, and we assume that the blood cells are moving directly toward the ultrasound source, show that the frequency (r of reflected waves detected by the apparatus is given by

(b) Show that the beat frequency is proportional to the speed of the blood cell if v

f1+ vlu f =1- olu