Exam 21: Mechanical Waves

A plucked guitar string produces a sound wave of frequency 0.44 kHz on a day when the speed of sound is 340 m/s. (a)What is the wavelength of the sound wave? (b)How much time elapses between the impacts of two adjacent compressions of the sound wave on your eardrum?

A train is traveling away from you at 120 km/h.It blows its whistle,and you hear a tone of 0.400 kHz.Take the speed of sound to be 340 m/s.What frequency does the whistle actually produce?

An pipe of length L that is open at both ends is resonating at its fundamental frequency.Which statement about the sound is correct?

Two motors in a factory are running at slightly different rates.One runs at 825.0 rpm and the other at $786.0 \mathrm { rpm } \text {. }$ You hear the sound intensity increase and then decrease periodically due to wave interference.How long does it take between successive instances of the sound intensity increasing?

If a wave has a speed of 362 m/s and a period of 4.17 ms,what is its wavelength?

Four waves are described by the following equations,where distances are measured in meters and times in seconds. I.y = 0.12 cos(3x - 21t) II.y = 0.15 sin(6x + 42t) III.y = 0.13 cos(6x + 21t) IV.y = -0.23 sin(3x - 42t) Which of these waves have the same period?

If the frequency of a violin string is to be increased by 20%,what change in tension must be applied?

A certain siren radiates sound uniformly in all directions.At a distance of 17 m from the siren,the intensity level is 49 db.How many watts of power does this siren put out? The threshold of human hearing is 1.0 × 10^-12 W/m².

An organ pipe open at both ends has a length of 0.80 m.If the velocity of sound in air is $340 \mathrm {~m} / \mathrm { s } \text {, }$ what is the frequency of the second harmonic of this pipe?

Two in-phase loudspeakers are 3.0 m apart.They emit sound with a frequency of 490 Hz.A microphone is placed half-way between the speakers and then moved along the line joining the two speakers until the first point of constructive interference is found.At what distance from that midpoint is that first point? The speed of sound in air is 343 m/s.

Transverse waves travel at $43.2 \mathrm {~m} / \mathrm { s }$ in a string that is subjected to a tension of $60.5 \mathrm {~N}$ If the string is $15.9 \text { m }$ long,what is its mass?

What are the wavelength (in meters)and frequency (in hertz)of a wave whose displacement is given by the equation y = 0.5 sin(0.20x + 120t),where x and y are in meters and t is in seconds?

A string that is 2.0 meters long is fixed at both ends and tightened until the wave speed is $18 \mathrm {~m} / \mathrm { s }$ What is the frequency of the standing wave shown in the figure?

A stretched string is observed to have four equal segments in a standing wave driven at a frequency of 480 Hz.What driving frequency will set up a standing wave with five equal segments?

What is the wave speed in a brass wire with a radius of 0.500 mm stretched with a tension of 125 N? The density of brass is 8.60 × 10³ kg/m³.