[tex]Dane:\\f_{z} = 800 \ Hz\\v_{z} = 108\frac{km}{h} = 108\cdot\frac{1000 \ m}{3600\ s}=30\frac{m}{s}\\v = 340\frac{m}{s}\\Szukane:\\f = ?\\\\Rozwiazanie\\\\f = f_{z}\cdot\frac{v}{v-v_{z}}\\\\f = 800 \ Hz\cdot\frac{340\frac{m}{s}}{340\frac{m}{s}-30\frac{m}{s}}}\\\\f = 800 \ Hz\cdot\frac{340\frac{m}{s}}{310\frac{m}{s}}\\\\\boxed{f \approx877,4 \ Hz}[/tex]
