Answer:
Speed of the ambulance is 32.7 metres per second.
Explanation:
Let the actual frequency of the siren be .
Frequency observed by me when ambulance is approaching = 540 Hz
Frequency observed by me when ambulance is moving away = 446 Hz
Let be the speed of sound and be the speed of ambulance.Then according to Doppler effect:
When source is moving towards observer,frequency observed is given as
= 540 Hz
When source is moving away from observer,frequency observed is given as
= 446 Hz
Taking and solving the above two equations by eliminating ,
we get