Musicians can use beats to tune their instruments. one oboe is properly tuned and plays the musical note a at exactly 440 hz. a second player sounds the same note and hears that her instrument is slightly "flat" (that is, at too low a frequency). playing at the same time as the first oboe, you hear two beats per second. what is the frequency of the second player's oboe? 4. a speaker suspended high in the air, away from other objects, emits one spherical wave with total energy 5 j. assume the waves travel at the speed of sound in air: 343 m/s. draw the wave 2 seconds and 5 seconds after it was emitted. label the total energy at each of these times. label the energy per unit area for each of these times. (this question requires explanation of your work but not the spec format.) 5. a rock band playing an outdoor concert produces sound at 120 db 5.0 m away from their single working loudspeaker. ignore sound reflected from walls and other objects and consider sound originating directly from the speakers. a. what is the sound intensity level 35 m from the speaker? b. how far away from the speaker should you stand to ensure the intensity does not exceed 80 db?