Physics (AS & A Level) · May / June 2017 · Paper 12 · Question 25

An ambulance travels along a straight road at a speed of 30.0 m s–1. Its siren emits sound of frequency 2000 Hz. The speed of sound in the air is 340 m s–1. The ambulance passes a man standing at the side of the road. What is the frequency of the sound heard by the man as the ambulance moves towards him and as the ambulance moves away from him?

1. Atowards man: 1820 Hz; away from man: 2180 Hz
2. Btowards man: 1840 Hz; away from man: 2190 Hz
3. Ctowards man: 2180 Hz; away from man: 1820 Hz
4. Dtowards man: 2190 Hz; away from man: 1840 Hz

As printed in the paper