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Physics 1: Unit 7 – More Mechanical Waves Please answer the following 20 questions (multiple choice/short answer)

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Physics 1: Unit 7 – More Mechanical Waves Please answer the following 20 questions (multiple choice/short answer). You DO NOT need to show your work. 1. What is the amplitude of the wave depicted here? Select one: a. 1.5 b. 8 c. 3 2. How does the wavelength of a sound when the receiver is moving away from the source compare to the wavelength if the source and receiver are stationary? Select one: a. The wavelength does not change. b. The wavelength is shorter. c. The wavelength is longer. 3. A light flickers 30 times in one second. What is the frequency of the light in Hertz? Select one: a. 15 b. 0.03 c. 30 d. 1 4. What type of interference gives rise to antinodes in standing waves? Select one: a. Destructive interference only. b. Both constructive and destructive interference happens at these sites. c. Constructive interference only. 5. If one firecracker going off registers 100 decibels. How many firecrackers would it take to register 120 decibels? Refer to the Threshold of Hearing and the Decibel Scale on this website to help with answering this. Select one: a. 100 b. 20 c. 10 d. 2 6. What happens to the frequency of a sound in order for the pitch to go up 2 octaves? Select one: a. It goes up 2 times. b. It goes up 2 hertz. c. It goes up 4 times. d. It goes up 4 hertz. 7. What is the velocity in m/s of the wave depicted here, if a crest can be seen going by every 4 seconds and each block represents 1 m? Select one: a. 32 b. 1 c. 2 d. 16 8. How does the amount of air that reaches your ear from mouth compare when I shout compared to when I whisper to you from across a large room. Select one: a. More reaches when you shout. b. Nothing is actually being transported. c. The amount is the same. d. More reaches when you whisper. 9. In a fluid medium (such as air or water), what type of wave is sound? Select one: a. Longitudinal (compression). b. It can be either type. c. Transverse. 10. What is the wavelength of the wave shown here? Select one: a. 1 b. 9 c. 1.8 d. 2 e. 0.9 11. A student holds a tuning fork that emits a sound at 256 Hz above a tube that is partially submerged in water. They find that they sound resonates the loudest when the tube is 0.33 m above the water. What is the speed of sound according to this experiment? Answer:__________________________________________________________ 12. If the speed of sound in water is 5000.0 m/s and a submarine receives a ping 5.0 seconds after sending it, how far away is the object the ping bounced off of? Answer:__________________________________________________________ 13. What happens to the frequency of a note played by an instrument if the wavelength is cut in half. Select one: a. The frequency will double. b. The frequency will not change. c. The frequency will be cut in half. 14. What happens to the velocity of the wave on a guitar string when the length of the string is cut in half? Select one: a. The velocity is doubled. b. The velocity does not change. c. The velocity is cut in half. 15. What happens to the Period of the wave on a guitar string when the length of the string is doubled? Select one: a. The Period is cut in half. b. The Period is doubled. c. The Period does not change. 16. What happens to the velocity of the wave on a guitar string when the string is loosened? Select one: a. The velocity goes down. b. The velocity goes up. c. The velocity does not change. 17. A 4.0 m long string has a standing wave on it with node on either end and two nodes in the middle when it vibrates with a frequency of 25 Hz, what is the speed of the wave? Answer:____________________________________________________ 18. Using the equation for the Doppler Effect: fobs = (v / (v - vsource)) * fsource Find the observed frequency of a whistle sounding at 440 Hz that is coming towards you at 25 m/s if the speed of sound is 330 m/s. Answer:______________________________________________________ 19. What quality of the wave must be matched up to the size of an object in some multiple in order for a sound to resonate on the object? Select one: a. Frequency b. Velocity c. Wavelength d. Amplitude 20. Two violins are attempting to play an A at 440 Hz at the same moment. However both violins are out of tune. One violin is slightly sharp at 444 Hz and the other is a little flat at 438 Hz. What is the beat frequency that will be heard when the two play together?