Physics help me

Question

Plz Help me to find out this question. - The frequency of an ambulance siren is 700 Hz with a speed of sound of 343 m/s. What frequency is heard by a stationary pedestrian at an intersection as the ambulance is approaching the pedestrian at a speed of 25m/s?

Answer 1

Frequency of the ambulance, f = 700 Hz

Speed of the ambulance siren sound , c = 343 m/s

Speed of the pedestrian, v = 25 m/s

Calculate the hearing frequency of ambulance siren when pedestrian is in stationary by using the Doppler shift equation:
For an ambulance is moving toward pedestrian, the frequency you hear goes up:
f ' = 700 × 343 / (343-25)

    = 755.03 Hz

Therefore, hearing frequency is 755.03 Hz