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hello can you please answer the question 9 i also add the table 2

hello can you please answer the question 9 i also add the table 2

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hello can you please answer the question 9 i also add the table 2

8.5 Questions 1. Researchers at the University of Adelaide, Australia, are proposing to control cyanobacteria with ultrasound. Research this topic using Internet resources, and answer the following questions: (a) What are cyanobacteria, and why are these bacteria important to control? (b) How are cyanobacteria traditionally controlled? (c) Why does the treatment propose using low-frequency ultrasound instead of high-frequency ultrasound? 2. An aircraft is flying at Mach 2. What does this mean? IK/U 3. An aircraft is travelling at Mach 0.83 in air at 10 °C. What is its speed in kilometres per hour? ™ C 4. Explain why the speed of sound varies in the different materials in Table 1 on page 395. Kru 5. In your own words, define (a) sound intensity, (b) loudness, and (c) decibel. U C 6. Why are different units required for sound intensity and loudness? Ku 7. In your own words, describe the concept of sound intensity. K/UC 8. Research the loudness level that is safe for listening to music on, for example, a personal music player. (a) Is there a difference in the level depending on the length of exposure? (b) Suppose the volume scale of a personal music player ranges from 0 to 10. Suppose also that each level corresponds to an increase in volume of 10 dB. So volume 1 = 30 dB and volume 3 = 50 dB, and so on. What is the loudest level you should set your personal music player to if you listen to music for 2 h a day? 9. A busy city street can produce sound levels near 90 dB, depending on the number of large vehicles (Figure 2). Calculate the ratio of the sound intensity of a power saw to that of a city street. Refer to Table 2 on page 395. Express your answer in words. ™Ⓒ Figure 2 10. A burglar coughs with an intensity of 2.35 x 10-7 W/m². The burglar alarm is sensitive to an intensity of 1.0 x 10-1⁰ W/m² and will ring if the detected sound is 30 dB greater than its detection threshold. Will the burglar's cough be detected? ™Ⓒ 11. The federal government supports the construction of noise barriers (also called sound baffles) on the sides of highways that run through residential areas to reduce residential noise. Research highway traffic noise barriers. (a) What are the barriers made of? (b) How do they work? (c) How effective are the barriers in reducing residential noise? GO TO NELSON SCIENCE
Transcribed Image Text:8.5 Questions 1. Researchers at the University of Adelaide, Australia, are proposing to control cyanobacteria with ultrasound. Research this topic using Internet resources, and answer the following questions: (a) What are cyanobacteria, and why are these bacteria important to control? (b) How are cyanobacteria traditionally controlled? (c) Why does the treatment propose using low-frequency ultrasound instead of high-frequency ultrasound? 2. An aircraft is flying at Mach 2. What does this mean? IK/U 3. An aircraft is travelling at Mach 0.83 in air at 10 °C. What is its speed in kilometres per hour? ™ C 4. Explain why the speed of sound varies in the different materials in Table 1 on page 395. Kru 5. In your own words, define (a) sound intensity, (b) loudness, and (c) decibel. U C 6. Why are different units required for sound intensity and loudness? Ku 7. In your own words, describe the concept of sound intensity. K/UC 8. Research the loudness level that is safe for listening to music on, for example, a personal music player. (a) Is there a difference in the level depending on the length of exposure? (b) Suppose the volume scale of a personal music player ranges from 0 to 10. Suppose also that each level corresponds to an increase in volume of 10 dB. So volume 1 = 30 dB and volume 3 = 50 dB, and so on. What is the loudest level you should set your personal music player to if you listen to music for 2 h a day? 9. A busy city street can produce sound levels near 90 dB, depending on the number of large vehicles (Figure 2). Calculate the ratio of the sound intensity of a power saw to that of a city street. Refer to Table 2 on page 395. Express your answer in words. ™Ⓒ Figure 2 10. A burglar coughs with an intensity of 2.35 x 10-7 W/m². The burglar alarm is sensitive to an intensity of 1.0 x 10-1⁰ W/m² and will ring if the detected sound is 30 dB greater than its detection threshold. Will the burglar's cough be detected? ™Ⓒ 11. The federal government supports the construction of noise barriers (also called sound baffles) on the sides of highways that run through residential areas to reduce residential noise. Research highway traffic noise barriers. (a) What are the barriers made of? (b) How do they work? (c) How effective are the barriers in reducing residential noise? GO TO NELSON SCIENCE
Table 2 Typical Sound Levels Type of sound threshold of human hearing normal breathing (at 1 m) typical whisper (at 1 m) empty classroom computer (at 1 m) library alarm clock (at 1 m) vacuum cleaner (at 2 m) diesel locomotive (at 30 m) motorcycle (at 10 m) NEL Typical sound intensity (W/m²) 1 x 10-12 1 x 10-11 1 x 10-10 1 x 10-⁹ 1 x 10-8 1 x 10-7 1 x 10-6 1 x 10-5 1 x 10-4 1 x 10-³ Sound level (dB) 0 10 20 30 40 50 60 70 80 90 Type of sound jet flyover (at 300 m) rock band jet aircraft engine (at 80 m), power saw threshold of pain military jet taking off space shuttle (at 180 m) sound cannon (at 1 m) 1 tonne TNT (at 30 m) (buildings 50 % destroyed) tornado atomic bomb Typical sound intensity (W/m²) 1 x 10-² 0.1 1.0 10 100 316 1 000 380 000 Sound level (dB) 100 110 120 130 140 145 150 175.8 1 x 10¹2 1 x 10¹3 8.5 Properties of Sound Waves 240 250 395
Transcribed Image Text:Table 2 Typical Sound Levels Type of sound threshold of human hearing normal breathing (at 1 m) typical whisper (at 1 m) empty classroom computer (at 1 m) library alarm clock (at 1 m) vacuum cleaner (at 2 m) diesel locomotive (at 30 m) motorcycle (at 10 m) NEL Typical sound intensity (W/m²) 1 x 10-12 1 x 10-11 1 x 10-10 1 x 10-⁹ 1 x 10-8 1 x 10-7 1 x 10-6 1 x 10-5 1 x 10-4 1 x 10-³ Sound level (dB) 0 10 20 30 40 50 60 70 80 90 Type of sound jet flyover (at 300 m) rock band jet aircraft engine (at 80 m), power saw threshold of pain military jet taking off space shuttle (at 180 m) sound cannon (at 1 m) 1 tonne TNT (at 30 m) (buildings 50 % destroyed) tornado atomic bomb Typical sound intensity (W/m²) 1 x 10-² 0.1 1.0 10 100 316 1 000 380 000 Sound level (dB) 100 110 120 130 140 145 150 175.8 1 x 10¹2 1 x 10¹3 8.5 Properties of Sound Waves 240 250 395
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