1. The Doppler Effect Textbook: 13.5 Homework: pg. 473 # 18, 19 pg. 476 # 64 – 71

3. The Doppler Effect  + if the source is moving away from the observer  - if the source is moving towards the observer

4. The Doppler Effect The frequency of a moving sound source appears to change according to a stationary observer  + if the source is moving away from the observer  - if the source is moving towards the observer

5. The Doppler Effect If both the source and observer are moving: Note: Top operations if the objects are moving away from each other, bottom if they are moving towards

6. The Doppler Effect If both the source and observer are moving: Note: Top operations if the objects are moving away from each other, bottom if they are moving towards

7. Explain why the Doppler effect occurs only if the sound-emitting object is moving relative to the listener. Calculate the apparent frequency heard by a person if a car traveling at 110 km/h emits a sound with frequency 450 Hz. Assume that the car is moving at the melting point of ice. a) away from the listener. b) toward the listener.

8. As a racing car zooms by you, its pitch decreases by 20%. If the speed of sound is 345 m/s, how fast is the car traveling?