1. 2.4 Addition of waves Simulation 17.1 http://bcs.wiley.com/he- bcs/Books?action=mininav&bcsId=4768&itemId=0470223553&assetId =160342&resourceId=15301&newwindow=true Constructive and Destructive Interference of Two PulsesConstructive and Destructive Interference of Two Pulses, SIM 25

2. Adding waves using the Superposition Principle

3. Beats with tuning forks

4. Simulation of Beats SIM 26 http://bcs.wiley.com/he- bcs/Books?action=mininav&bcsId=4768&itemId=0470223553&assetId=160 342&resourceId=15301&newwindow=true

5. Beat Wave Pattern A 10-Hz sound wave and a 12-Hz sound wave, when added together, produce a wave with a beat frequency of 2 Hz. The drawings show the pressure patterns (in blue) of the individual waves and the pressure pattern (in red) that results when the two overlap.

6. Beats Musical instruments are tuned by listening to the beat frequency. For instance, a piano tuner listens to the beats produced between the string and a source with the correct frequency. The piano tuner adjusts the tension in the string until the beats vanish, ensuring that the string is vibrating at the correct frequency.

7. 2.6 The Doppler Effect When the truck is stationary, the wavelength of the sound is the same in front of and behind the truck.

8. 2.6 The Doppler Effect When the truck is stationary, the wavelength of the sound is the same in front of and behind the truck. When the truck is moving, the wavelength in front of the truck becomes smaller, while the wavelength behind the truck becomes larger. Doppler effect is the change in frequency or pitch of the sound detected by an observer because the sound source and the observer have different velocities with respect to the medium of sound propagation.

9. Application of Doppler Effect Nexrad: Next Generation Weather Radar