1. Homework and Review Questions
Sound Connections
Homework and Review Questions

2. Question #1
Through which medium does sound travel the fastest? Explain your answer
Gas
Liquid
solid

3. Question #2
Lightning strikes 2.5 miles away on a hot (30°C) summer night. How long will it take for the sound of thunder to reach your ears?

4. Question #3
A train at rest emits a sound at a frequency of 1000 Hz. An observer in a car travels away from the sound source at a speed of 30 m/s. What is the frequency heard by the observer? Assume temperature of air is 20°C

5. Question #4
An airplane traveling with half the speed of sound (v = 172 m/s) emits a sound of frequency 5.0 kHz. At what frequency does a stationary listener hear the sound (a) as the plane approaches? (b) after it passes?

6. Question #5
Two trains on separate tracks move towards each other. Train A has a speed of 130 km/h and Train B has a speed of 90 km/h. Train B blows its horn, emitting a frequency of 500 Hz. What is the frequency heard by the engineer on train A?

7. Question #6
A supersonic jet breaks the sound barrier while it is 7,000 m directly over you. How much time will it take the sonic boom to reach your ears it sound moves at 345 m/s? How fast is a plane traveling if it moves at Mach 3?

8. Question #7
List 5 different examples of interactions where the pitch changed significantly between two objects as one or both moved towards each other.
What characteristics do the examples have in common?

9. Question #8
explain why the sound changes when the source of object moves past the observer (detector)

10. Question #9
The engine of a motorcycle hums at 85 Hz. If the motorcycle travels toward a resting observer at 29.6 m/s, what frequency does the observer hear? Use 343 m/s as the speed of sound.

11. Question #10
A submarine is traveling toward a stationary detector. If the submarine emits a 260 Hz sound that is received by the detector as a 262 Hz sound, how fast is the submarine traveling? Use 1533 m/s for the speed of sound in seawater

12. 4 Bonus points
Send me a copy of a short cell phone video of a good real life example of the Doppler effect
Want both sound and video.
Send it to me by attachment to an
in , tell me the software used to produce the video
Or post it google, youtube video and me directions on how to view it