1. An audio speaker producing a steady sound at an outdoor concert is 30 ft away from you. If you move to a position where the speaker is 84 ft distant, by what factor will the amplitude of the sound change? 2. A person stands directly in front of two speakers that are emitting the same pure tone. The person then moves to one side until no sound is heard. At that point, the person is 5.65 m from one of the speakers and 5.67 m from the other. What is the frequency (in Hz) of the tone being emitted? (Assume air temperature to be 20C.) 3. A baseball fan sitting in the "cheap seats" is d = 177 m from home plate (see the figure below). How much time elapses between the instant the fan sees a batter hit the ball and the moment the fan hears the sound? (Assume the speed of sound is 344 m/s, and the vertical distance can be ignored.) 4. Approximately how many times louder is a 130-dB sound than a 80-dB sound? 5. Ultrasound probes can resolve structural details with sizes approximately equal to the wavelength of the ultrasound waves themselves. What is the size of the smallest feature observable in human tissue when examined with 18-MHz ultrasound? The speed of sound in human tissue is 1,540 m/s. 6. A sound pulse emitted underwater reflects off a school of fish and is detected at the same place 0.04 s later (see the figure below). How far away are the fish