Answer: 15.35 m/s
Explanation: 15.35 m/s
[tex]$From the Doppler effect$f^{\prime}=\left(\frac{v \pm v_{0}}{v \pm v_{s}}\right) f_{s}$[/tex]
[tex]\begin{aligned}&f^{\prime}=1920 \mathrm{~Hz} ; \ \ V=343 \mathrm{~m} / \mathrm{s} \\&f=2010 \mathrm \ \text{{H}z} \\&V_S=0 \text { As police car is stationary }\end{aligned}[/tex]
[tex]\begin{aligned}1920 &=\left(\frac{343 \pm v_{0}}{343}\right) \times 2010 \\1920 &=\left(\frac{343-v_{0}}{343}\right) \times 2010 \\ -v_{0} &=-15.35 \mathrm{~m/s} \\v_{0} &=15.35 \mathrm{~m} / \mathrm{s}\end{aligned}[/tex]
Therefore, the second car is driving at 15.35 m/s
