Beats, Doppler, Resonance Pipes, and Sound Intensity Printer Friendly Version
This worksheet is a one-time submission. All answers must be accompanied by a well-organized, neatly written paper copy showing every step of your calculations. This EC worksheet must be submitted ONLINE prior to 11 PM on Tuesday, Nov 27th. It is an optional assignment. In addition to submitting your answers, you must turn in supporting calculations ON PAPER when you walk into class on the 28th.

 An half-open organ pipe resonates to a frequency of 440 hz when its temperature is 20ºC. What beat frequency would be heard between this pipe at 20ºC and an identical second pipe at 25ºC if they were sounded together?

 An open tube open is 45.0 cm long. At 15ºC, it will resonate under the action of a 392 hz sound source provided that the source is receding from it at a constant velocity. How fast must the source be traveling for this to happen?

 An approaching sound source is traveling at 20 m/sec towards a stationary observer who has an identical sound source. Both sources emit identical 440-hz signals. When the temperature is 25ºC, how many beats will the stationary observer hear when the signals from the moving source reach his position?

 A sound source emits waves that have equal intensity in all directions. The intensity of the waves at a distance of 2.5 meters from the source is 1.91 x 10-4 W/m2. If another listener is located 1.25 meters away, what sound level intensity does he hear?