Question

I need some help w/ this:

Answer 1

Answer:

The velocity of the police car is, v = 17.798 m/s

Explanation:

Given data,

The actual frequency of the siren, f = 2010 Hz

The observed frequency of siren is, f' = 2120 Hz

The velocity of the observer, v' = 0 m/s

The velocity of the source, v = ?

The formula for Doppler effect,

                            $f'=\frac{(V+v')}{(V-v)}f$

Where,

                         V - velocity of sound waves in air.

                          $v=V-(V+v')\frac{f}{f'}$

Substituting the given values,

                         $v=343-(343+0)\frac{2010}{2120}$

                                 v = 17.798 m/s

Hence, the velocity of the police car is, v = 17.798 m/s