The security alarm on a parked car goes off and produces a frequency of 960 Hz. The speed of sound is 343 m/s. As you drive toward this parked car, pass it, and drive away, you observe the frequency to change by 75 Hz. At what speed are you driving

Explanation:

Given

The frequency of the source is

Change in frequency is

Speed of sound

Suppose is the velocity of the observer

Doppler frequency is given by

Here, the source is at rest

While approaching source, frequency is

While leaving, frequency is

The difference in the frequency is

here we know that ball will drop down by total distance 3.2 m

so here we know that

now using kinematics

now in the same time it will cover horizontal distance of 0.75 m

so speed of the ball will be

v 154.9= 0.9 length length s little over 154.9cm