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Group A—Continued Group B—Continued
5. A baseball fan is 150.0 m from the home plate. How much time 5. How much time will elapse between seeing and hearing an event
elapses between the instant the fan sees the batter hit the ball and that happens 400.0 meters from you?
the moment the fan hears the sound?
6. An echo is heard from a building 0.500 s after you shout “hello.” 6. An echo bounces from a building exactly 1.00 s after you honk
How many feet away is the building if the air temperature is your horn. How many feet away is the building if the air
20.0°C? temperature is 20.0°C?
7. A sonar signal is sent from an oceangoing ship, and the signal 7. A submarine sends a sonar signal, which returns from another
returns from the bottom 1.75 s later. How deep is the ocean ship 2.250 s later. How far away is the other ship if the speed of
beneath the ship if the speed of sound in seawater is 1,530 m/s? sound in seawater is 1,530.0 m/s?
8. A sound wave in a steel rail of a railroad track has a frequency of 8. A student under water clicks two rocks together and makes a
660 Hz and a wavelength of 9.0 m. What is the speed of sound in sound with a frequency of 600.0 Hz and a wavelength of 2.5 m.
this rail? What is the speed of this underwater sound?
9. According to the condensed steam released, a factory whistle 9. You see condensed steam expelled from a ship’s whistle 2.50 s
blows 2.5 s before you hear the sound. If the air temperature is before you hear the sound. If the air temperature is 20.0°C, how
20.0°C, how many meters are you from the whistle? many meters are you from the ship?
10. Compare the distance traveled in 8.00 s as a given sound moves 10. Compare the distance traveled in 6.00 s as a given sound moves
through (a) air at 0°C and (b) a steel rail. through (a) water at 25.0°C and (b) seawater at 25.0°C.
11. A vibrating object produces periodic waves with a wavelength of 11. A tuning fork vibrates 440.0 times a second, producing sound
50 cm and a frequency of 10 Hz. How fast do these waves move waves with a wavelength of 78.0 cm. What is the velocity of
away from the object? these waves?
12. The distance between the center of a condensation and the 12. The distance between the center of a condensation and the
center of an adjacent rarefaction is 1.50 m. If the frequency is center of an adjacent rarefaction is 65.23 cm. If the frequency is
112.0 Hz, what is the speed of the wave front? 256.0 Hz, how fast are these waves moving?
13. Water waves are observed to pass under a bridge at a rate of one 13. A warning buoy is observed to rise every 5.0 s as crests of waves
complete wave every 4.0 s. (a) What is the period of these waves? pass by it. (a) What is the period of these waves? (b) What is the
(b) What is the frequency? frequency?
14. A sound wave with a frequency of 260 Hz moves with a velocity 14. Sound from the siren of an emergency vehicle has a frequency of
of 330 m/s. What is the distance from one condensation to the 750.0 Hz and moves with a velocity of 343.0 m/s. What is the
next? distance from one condensation to the next?
15. The following sound waves have what velocity? 15. The following sound waves have what velocity?
a. Middle C, or 256 Hz and 1.34 m λ. a. 20.0 Hz, λ of 17.2 m.
b. Note A, or 440.0 Hz and 78.0 cm λ. b. 200.0 Hz, λ of 1.72 m.
c. A siren at 750.0 Hz and λ of 45.7 cm. c. 2,000.0 Hz, λ of 17.2 cm.
d. Note from a stereo at 2,500.0 Hz and λ of 13.7 cm. d. 20,000.0 Hz, λ of 1.72 cm.
16. What is the speed of sound, in ft/s, if the air temperature is: 16. How much time is required for a sound to travel 1 mile (5,280.0 ft)
a. 0.0°C? if the air temperature is:
b. 20.0°C? a. 0.0°C?
c. 40.0°C? b. 20.0°C?
d. 80.0°C? c. 40.0°C?
d. 80.0°C?
17. An echo is heard from a cliff 4.80 s after a rifle is fired. How 17. A ship at sea sounds a whistle blast, and an echo returns from the
many feet away is the cliff if the air temperature is 43.7°F? coastal land 10.0 s later. How many km is it to the coastal land if
the air temperature is 10.0°C?
18. The air temperature is 80.00°F during a thunderstorm, and 18. How many seconds will elapse between seeing lightning and
thunder was timed 4.63 s after lightning was seen. How many hearing the thunder if the lightning strikes 1 mi (5,280 ft) away
feet away was the lightning strike? and the air temperature is 90.0°F?
19. If the velocity of a 440 Hz sound is 1,125 ft/s in the air and 19. A 600.0 Hz sound has a velocity of 1,087.0 ft/s in the air and a
5,020 ft/s in seawater, find the wavelength of this sound in velocity of 4,920.0 ft/s in water. Find the wavelength of this sound
(a) air and (b) seawater. in (a) the air and (b) the water.

138 CHAPTER 5 Wave Motions and Sound 5-24