Exam 16: Sound

A car traveling at 22 m/s honks its horn as it directly approaches the side of a large building.The car horn plays a long sustained note with frequency f₀ = 230 Hz (in the car's frame of reference).The sound is strongly reflected off the building back to the driver.What is the frequency of the reflected wave that the driver hears?

A pipe with one end closed and the other end open has a fundamental frequency of 120 Hz.If the closed end is opened,what is the fundamental frequency of this pipe with both ends open?

The sound of 40 decibels is

The sound level in the middle of a rave is 90.0 dB.What is the sound intensity at this location?

A source travelling to the right at a speed of 5 m/s emits a sound wave which is reflected off a reflector travelling to the left at a speed of 5 m/s.If the frequency of the reflected sound wave detected by a listener back at the source is 100 Hz,what is the frequency of the wave emitted at the source?

A police car is approaching you,traveling eastward at a speed of 31.0 m/s sounds his siren (frequency of 1050 Hz).What is your velocity if you hear a frequency of 1090 Hz.The speed of sound is 344 m/s.

Two adjacent frequencies of longitudinal standing waves in a half-open pipe are 1500 Hz and 1620 Hz.What is the fundamental frequency of the longitudinal standing waves in this half-open pipe?

The intensity level of the sound produced by loud rock music is 120 dB.The power incident on an eardrum of area 0.4 cm² from this sound level is

What is the sound intensity 2.65 m away from a 125 W speaker that is emitting sound uniformly in all directions?

A sound meter placed 5.0 m away from a speaker registers a sound level of 60 dB.If the volume on the speaker is turned down so that the power is reduced by a factor of 40,what will the sound meter now read?

At a certain distance from a sound source the intensity is measured to be 80 dB.What is the intensity of the sound in W/m²?

A pipe open at both ends has a fundamental frequency of 120 Hz.If one end of the pipe is then closed,what is the fundamental frequency of this pipe with one end closed?

Find the resonant frequency of the ear canal.Treat it as a half-open tube of diameter 8 mm and length 27 cm.Assume the temperature inside the ear canal is body temperature (37 ^$\circ$ C).

A source travelling to the right at a speed of 5 m/s emits a sound wave which is reflected off a reflector travelling to the left at a speed of 5 m/s.If the frequency of the reflected sound wave detected by a listener back at the source is 100 Hz,what is the frequency of the wave emitted at the source?

On a hot day the temperature reaches 40.0 degree Celsius.A car,traveling 20.0 m/s,honks his horn (f = 400.0Hz).What frequency does a stationary pedestrian hear if the car is moving away from him.

The sound level of sound decreases by 10 dB as it pass through a wall of uniform composition.If the wall is replace with a similar wall having the same thickness,but an absorption coefficient double that if the first wall,the sound level of the same sound will decrease by ____ as it passes through the new wall.

One speaker is located at the origin and the other is located at (x,y)= (0,3.00 m).The speakers emit identical sound waves of wavelength 2.00 m which are initially in phase.Where does constructive interference occur?

One piano is at rest,and another one approaches at 3.4 m/s.Both pianists are playing middle C (512 Hz).What beats does the pianist at rest hear as a result of the Doppler shift? (Use 340 m/s for v_sound.)

You are standing directly between two speakers that are separated by 40 m.The two speakers are each playing a pure tone of 256 Hz.You begin running directly towards one of the speakers at 3.0 m/s.What beat frequency do you detect?

You are standing directly between two speakers that are separated by 30 m.The two speakers are each playing a pure tone of 256 Hz.You begin running directly towards one of the speakers and you measure a beat frequency of 6.0 Hz.How fast are you running?