1) Amy and Rory are driving in the same direction with the same speed along a straight road. Rory is following Amy. If Amy and Rory both sound their horns, does either person hear a different frequency compared to if the cars were stationary?

2) Rose is singing an operatic note at 852 Hz. Jack is running towards Rose with speed 5.53 m/s. What frequency does Jack hear?

You may assume the speed of sound in air is 343 m/s.

3) A train is stopped at the station and is sounding its horn with frequency 680 Hz. Martha is moving away from the train with speed 26.5 m/s. What frequency does Martha hear?

You may assume the speed of sound in air is 343 m/s.

4) A bobber bobs up and down in water, creating waves with speed 2.40 m/s and frequency 6.55 Hz. Mickey is in a boat approaching the source with speed 16.9 m/s. What is the frequency (in Hz) of the waves that Mickey observes?

5) Donna blasts an air horn with frequency 442 Hz. While she holds the air horn, she runs with speed 5.87 m/s towards a cliff face. What is the frequency (in Hz) of the echo that Donna hears?

You may assume the speed of sound in air is 345 m/s.

6) Amy is driving along a highway at 19.4 m/s when she hears the siren of an ambulance traveling in the opposite direction on the other side of the highway. When the vehicle is approaching Amy, she hears the frequency of the siren as 2900 Hz, but when it is past her, she hears a frequency of 2210 Hz. The speed of sound in air is 343 m/s. What is the speed of the ambulance (in m/s)?

7) What is the frequency of the ambulance's siren (in Hz)?