Honors Physics

# Questions - Week 27

1. The speed of sound in air is over 700 miles/hour, but the air is certainly not moving that fast! If it isn't the medium that's moving, what does it mean to talk about the speed of a wave?
2. Amplitude is a feature of a wave, but it means different things with different types of wave. What is a general definition of amplitude?
3. What are the two types of waves discussed in class? What are their defining characteristics? Give an example of each.
4. Draw a pressure vs. length graph for a sound wave. Label one amplitude, and one wavelength.
5. If the speed of sound is 345 m/s what is the frequency for a 1.0 m wavelength?
6. Shake a rope so that it makes three "humps" (known more formally as anti-nodes). If you shake the rope up & down 12 times in 9.5 seconds while you and your partner are 2.5 m apart, what is the speed of the wave through the rope?
7. What are the three subjective properties of sound?
8. What are the three objective properties of sound, and how do they relate to the subjective properties?
9. What is the intensity of a 75 dB sound?
10. If 4,500,000 J of energy were delivered into the air over 1.5 seconds, what would be the intensity at a distance of 25 m?
11. If five people were each talking at 65 dB, what would be the intensity level with them all talking at the same time?
12. Is pitch directly proportional or indirectly proportional to frequency?
13. Two singers singing the same note, at the same loudness, will usually sound different from each other. Why?