Exam 14: Waves and Sound

A fisherman fishing from a pier observes that the float on his line bobs up and down,taking 2.4 s to move from its highest point to its lowest point.He also estimates that the distance between adjacent wave crests is 48 m.What is the speed of the waves going past the pier?

The intensity of the waves from a point source at a distance d from the source is I.At what distance from the sources is the intensity equal to 2I?

A 4.0-g string is 0.36 m long and is under tension.The string vibrates at 500 Hz in its third harmonic.What is the wavelength of the standing wave in the string?

Light from a laser forms a 1.31-mm diameter spot on a wall.If the light intensity in the spot is What is the power output of the laser? Assume that all the light emitted by the laser hits the spot.

A 2.0-g string that is 0.67 m long is under tension.The string vibrates at 700 Hz tone in its third harmonic,and this vibration causes a sound wave.What is the wavelength of the sound? The speed of sound in air is 344 m/s.

A string of mass m is under tension,and the speed of a wave in the string is v.What will be the speed of a wave in the string if the mass of the string is increased to 2m but with no change in the length or tension?

A 4.0-g string is 0.39 m long and is under tension.The string vibrates at 600 Hz in its third harmonic.What is the tension in this string?

A standing wave is oscillating at 950 Hz on a string,as shown in the figure.What is the wave speed?

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

A string fixed at both ends is vibrating in one of its harmonics.If we now increase only the frequency at which the string is vibrating,which of the following characteristics do we also increase? (There could be more than one correct choice. )

One of the harmonics of a column of air in a tube that is open at both ends has a frequency of 448 Hz,and the next higher harmonic has a frequency of 576 Hz.What is the fundamental frequency of the air column in this tube?

If a string fixed at both ends resonates in its fundamental mode with a frequency of 150 Hz,at which of the following frequencies will it not resonate? (There could be more than one correct choice. )

What is the frequency of the fundamental mode of vibration of a steel piano wire stretched to a tension of 440 N? The wire is 0.600 m long and has a mass of 5.60 g.

One of the harmonics of a string fixed at both ends has a frequency of 52.2 Hz and the next higher harmonic has a frequency of 60.9 Hz.What is the fundamental frequency of the string?

A piano wire of linear mass density 0.0050 kg/m is under a tension of 1350 N.What is the wave speed in this wire?

If a guitar string has a fundamental frequency of 500 Hz,which one of the following frequencies can set the string into resonant vibration?

You are moving at 120 km/h toward a stationary train.The train blows its 0.400-kHz whistle.Take the speed of sound to be 340 m/s.What frequency do you hear?

The intensity at a distance of 6.0 m from a source that is radiating equally in all directions is 6.0 × 10^-10 W/m².What is the power emitted by the source?

Two speakers are placed side by side and driven by the same frequency of 0.50 kHz.If the distance from a person to one speaker is 5.0 m and the person detects little or no sound,which of the following is a possible the distance from the person to the other speaker? The sound speed in the room is 340 m/s.

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