Chapter 20: Problem 55

Question:        The $\nu_0 = 15.8\ {\rm kHz}$ whine of the turbine engines in the jet engines of an aircraft moving with speed $v_1=193\ {\rm m/s}$is heard at what frequency by the pilot of a second craft trying to overtake the first at a speed of $v_2 = 246 \ {\rm m/s}$?

Solution:         We have the source and the observer moving in the same direction, and so we have

$$\nu_2 \nu_1\left( { c+v_2\over c+v_1}\right)$$ =

$$15.8 \ {\rm kHz}\ \left( { 343+246\over 343+193}\right) \ = \ 17.36 \ {\rm kHz} \ \ \ .$$ = (11)