1. Sound

2. Sound Intensity Intensity – the rate of energy flow through a given area

3. Units for Power – watt (W) Units for distance – meter (m) Units for intensity – watts per meters squared (W/m 2 )

4. Sound Intensity Intensity and frequency determine which sounds are audible Threshold of Hearing – softest sounds heard by humans Threshold of Pain – loudest sounds human ears can tolerate

6. Sound Intensity Decibel level – relative intensity, measured in decibels (dB)

8. Resonance Resonance – when the frequency of a force applied to an object matches the object’s natural frequency

9. Tacoma Narrows Bridge Collapse

10. Human Ear The ear transmits vibrations that cause nerve impulses

12. What is the intensity of the sound waves produced by a trumpet at a distance of 3.2 m when the power output of the trumpet is 0.20 W?