• Targets • recognize the effects of the diffraction of sound waves • recognize the effects of the interference of sound waves • perform calculations involving the reflection of sound waves • Do Now • put solutions to homework on board • Homework • study
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Targets recognize the effects of the diffraction of sound waves
Targets recognize the effects of the diffraction of sound waves recognize the effects of the interference of sound waves perform calculations involving the reflection of sound waves Do Now put solutions to homework on board Homework study. Sound Reflection. - PowerPoint PPT Presentation
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• Targets• recognize the effects of the
diffraction of sound waves• recognize the effects of the
interference of sound waves• perform calculations involving the
reflection of sound waves
• Do Now• put solutions to homework on board
• Homework• study
• when a sound wave encounters a change of medium, a portion of the energy is reflected
• the rest of the energy is transmitted
• the greater the dissimilarity of the mediums, the greater the amplitude of the reflected sound wave
• same principle as that observed with waves in the slinky and heavy coil
• You stand at the top of a well and shout into the well. After 0.4 seconds you hear your echo. The speed of sound in the well is 343 m/s. How deep is the water in the well?
• 69 m
Echo Sample Problem 2
• You sing a middle C, 256 Hz, in the middle of a large canyon to see how it echos
a.What is the wavelength of sound wave if the speed of sound in air is 343 m/s?
b.If it takes 0.75 seconds for the wave to return from one side of the canyon and 0.81 seconds for the wave to return from the other side, how wide is the canyon?
Sound Diffraction
• the bending of waves around small obstacles and the spreading out of waves beyond small openings
More practice problems1. The speed of sound at 20°C is 343 m/s. If
you hear the crack of a gun 0.7 seconds after you see the gun shot, how far away is the shooter from you?
2. Two tuning forks are struck at the same time, one with a frequency of 256 Hz and one with a frequency of 280 Hz. What is the beat frequency produced?
3. What is the frequency of a sound with a wavelength of 30 cm if the speed of sound is 343 m/s?
More practice problems4. A sound with a frequency of 550 Hz has a
wavelength of 5 m in a pipe of iron. What is the speed of sound in this pipe?
5. If the speed of sound in air can be found by the equation v = 331 m/s + (0.6m/s)T. At what temperature does sound have a speed of 400 m/s?
6. A wave vibrates 135 times per second. What is the period of this wave?
7. The wavelength of a sound wave is 10 m and it has a speed of 343 m/s. What is the period of the wave?