Exam 16: Sound and Hearing

Shock waves occur when

Two loudspeakers placed 6.0 m apart are driven in phase by an audio oscillator whose frequency range is to A point P is located from one loudspeaker and 3.6 m from the other.The speed of sound is 344 m/s.The frequency produced by the oscillator,for which constructive interference of sound occurs at point P,is closest to

The intensity level of a "Super-Silent" power lawn mower at a distance of 1.0 m is 100 dB.You wake up one morning to find that four of your neighbors are all mowing their lawns using identical "Super-Silent" mowers.When they are each 20 m from your open bedroom window,what is the intensity level of the sound in your bedroom? You can neglect any absorption,reflection,or interference of the sound.The lowest detectable intensity is

Two in-phase loudspeakers are some distance apart.They emit sound with a frequency of .You move between the speakers,along the line joining them,at a constant speed of .What beat frequency do you observe? The speed of sound in the room is .

You are driving along a highway at 35.0 m/s when you hear the siren of a police car approaching you from behind and you perceive the frequency as 1310 Hz.You are relieved that he is in pursuit of a different speeder when he continues past you,but now you perceive the frequency as 1240 Hz.What is the frequency of the siren in the police car? The speed of sound in air is .

A pipe that is 0.46 m long and open at both ends vibrates in the second overtone with a frequency of In this situation,the distance from the center of the pipe to the nearest antinode is closest to

A carousel that is 5.00 m in radius has a pair of 600-Hz sirens mounted on posts at opposite ends of a diameter.The carousel rotates with an angular velocity of 0.800 rad/s.A stationary listener is located at a distance from the carousel.The speed of sound is 350 m/s.The maximum beat frequency of the sirens at the position of the listener is closest to

An airplane flying faster than the speed of sound of 340 m/s produces a shock wave that makes an angle of 50° with the direction the plane is flying.What is the speed of the plane?

At a distance of 2.00 m from a point source of sound,the intensity level is 80.0 dB.What will be the intensity level at a distance of 4.00 m from this source? The lowest detectable intensity is .

A string 40.0 cm long of mass 8.50 g is fixed at both ends and is under a tension of .When this string is vibrating in its third OVERTONE,you observe that it causes a nearby pipe,open at both ends,to resonate in its third HARMONIC.The speed of sound in the room is (a)How long is the pipe? (b)What is the fundamental frequency of the pipe?

A boy on a bicycle approaches a brick wall as he sounds his horn at a frequency 400.00 Hz.The sound he hears reflected back from the wall is at a frequency 408.00 Hz.At what is the speed is the boy riding his bicycle toward the wall? Assume the speed of sound in air is .

Consider a pipe of length L that is open at both ends.What are the wavelengths of the three lowest-pitch tones produced by this pipe?

A pipe that is 120 cm long resonates to produce sound of wavelengths 480 cm,160 cm,and 96 cm but does not resonate at any wavelengths longer than these.This pipe is

The sound from a single source can reach point O by two different paths.One path is long and the second path is 21.0 m long.The sound destructively interferes at point O.What is the minimum frequency of the source if the speed of sound is 340 m/s?

The lowest-pitch tone to resonate in a pipe of length L that is open at both ends is 200 Hz.Which one of the following frequencies will NOT resonate in the same pipe?

An enclosed chamber with sound absorbing walls has a opening for an outside window.A loudspeaker is located outdoors, away and facing the window.The intensity level of the sound entering the window space from the loudspeaker is .Assume the acoustic output of the loudspeaker is uniform in all directions and that the acoustic energy incident upon the ground is completely absorbed and therefore is not reflected into the window.The threshold of hearing is .The acoustic power entering through the window space is closest to

A certain crying baby emits sound with an intensity of .What is the intensity level due to a set of five such crying babies,all crying with the same intensity? You can neglect any absorption,reflection,or interference of the sound.The lowest detectable intensity is 1.0 × 10^-12 W/m².

Radio station KBOB broadcasts at a frequency of 85.7 MHz on your dial using radio waves that travel at 3.00 × 10⁸ m/s.Since most of the station's audience is due south of the transmitter,the managers of KBOB don't want to waste any energy broadcasting to the east and west.They decide to build two towers,transmitting in phase at exactly the same frequency,aligned on an east-west axis.For engineering reasons,the two towers must be AT LEAST 10.0 m apart.What is the shortest distance between the towers that will eliminate all broadcast power to the east and west?

A string,0.28 m long and vibrating in its third harmonic,excites an open pipe that is 0.82 m long into its second overtone resonance.The speed of sound in air is 345 m/s.The speed of transverse waves on the string is closest to

A policeman in a stationary car measures the speed of approaching cars by means of an ultrasonic device that emits a sound with a frequency of 41.2 kHz.A car is approaching him at a speed of 33.0 m/s.The wave is reflected by the car and interferes with the emitted sound producing beats.What is the frequency of the beats? The speed of sound in air is .