14. You hear the sound of the firing of a distant cannon 6.0 s after seeing the flash. How far are you from the cannon (assuming the speed of sound at that moment is 343 m/s)? 15. What happens to pitch when the frequency of sound waves increases? 16. How is a sound affected by a larger amplitude of the wave? 17. Which sound wave will have a greater amplitude, a wave with many compressions or a wave with few compressions? 18. The intensity of a sound wave at a fixed distance from a speaker vibrating is 0.600 W/m2. If the power is 5.24 W determine the distance at which the speaker is located. 19. If the wavelength of a 4.40 x 102 Hz sound in freshwater is 3.0 m, what is the speed of sound in water? 20. When an automobile moves towards a listener, the sound of its horn seems relatively a. low pitched b. high pitched c. normal 21. When the automobile moves away from the listener, its horn seems a. low pitched b. high pitched c. normal 22. The changed pitch of the Doppler effect is due to changes in a. wave speed b. wave frequency 23. Circle the letter of each statement about the Doppler Effect that is true. a) It occurs when a wave source moves towards an observer. b) It occurs when an observer moves towards a wave source. c) It occurs when a wave source moves away from an observer. d) It occurs when an observer moves away from a wave source