If no information is given, assume the speed of sound to be 345 m/s.

1. An explosion occurs at a distance of 6 km from a person on a day when the temperature is 14°C. How long after the explosion did the person hear it? Ans: 17.65 sec
2. A car is moving at 20 m/s along a straight road with its 500 Hz horn sounding. You are standing at the side of the road. What frequency do you hear as the car is approaching? Ans: 530.77 Hz
3. A car is moving at 20 m/s along a straight road with its 500 Hz horn sounding. You are standing at the side of the road. What frequency do you hear as the car is receding from you? Ans: 472.60 Hz
4. When a car approaches, sounding its horn, a stationary observer detects a frequency of 380 Hz. When it recedes from the stationary observer, sounding its horn, the observer detects a frequency of 360 Hz. The horn has a frequency of 370 Hz. What is the speed of the car? Ans: 9.05 m/s
5. A cliff is 12 m high. You drop a stone from the top of the cliff. How long does it take for you to hear the sound of its "thud?" Ans: 1.60 sec
6. A student uses a water-filled tube to determine the speed of sound. The tube is 1 m tall. He detects a resonance position when the water level is 55 cm tall that corresponds to the third harmonic when a 575 Hz tuning fork is used. What is the wavelength of the sound wave? What speed of sound did he experimentally determine? Ans: 0.60 m; 345 m/s
7. An open pipe is used to determine the speed of sound to be 335 m/s using a 324 Hz tuning fork. What is the wavelength of the sound wave? If this is the position of the third harmonic, how long is the pipe? Ans: 1.034 m; 1.551 m
8. Repeat for a closed pipe. Ans: 1.034 m; 0.7755 m

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