Exam 16: Sound and Hearing

A certain source of sound waves radiates uniformly in all directions.At a distance of 20 m from the source the intensity level is 51 db.What is the total acoustic power output of the source,in watts? (Note: The reference intensity I₀ is

A 0.25-m string,vibrating in its sixth harmonic,excites a 0.96-m pipe that is open at both ends into its second overtone resonance.The speed of sound in air is 345 m/s.The common resonant frequency of the string and the pipe is closest to

A woman is riding a bicycle at 18.0 m/s along a straight road that runs parallel to and right next to some railroad tracks.She hears the whistle of a train that is behind.The frequency emitted by the train is 840 Hz,but the frequency the woman hears is 778 Hz.Take the speed of sound to be 340 m/s. (a)What is the speed of the train,and is the train traveling away from or toward the bicycle? (b)What frequency is heard by a stationary observer located between the train and the bicycle?

In a resonating pipe that is open at both ends,there

A 1.30-m long gas column that is open at one end and closed at the other end has a fundamental resonant frequency 80.0 Hz.What is the speed of sound in this gas?