Sound Waves Questions and Answers

A source emitting the sound of frequency 400 Hz is tied to a string of length 1 m and rotated with an angular speed of 30 rad/s in the horizontal plane. Maximum frequency observed by an stationary observer is n x 10 Hz. Find n. (Vsound = 330 m/s)

A source of sound of frequency 300 Hz is moving rapidly toward a fixed wall with a velocity of 30 m/s. If the speed of sound is 330 m/s, then the frequency of reflected wave observed by stationary observer will be n x 10 Hz. Find n.

The toadfish makes use of resonance in a closed tube to produce very loud sounds. The tube is its swim bladder, used as an amplifier. The sound level of this creature has been measured as high as 100 dB. (a) Calculate the intensity of the sound wave emitted. (b) What is the intensity level if three of these toadfish try to make a sound at the same time?

Two loudspeakers in a 20°C room emit 700 Hz sound waves along the x-axis. If the speakers are in phase, what is the smallest distance between the speakers for which the interference of the sound waves is perfectly destructive?

A flute player hears four beats per second when she compares her note to a 659 Hz tuning fork (the note E). She can match the frequency of the tuning fork by pulling out the "tuning joint" to lengthen her flute slightly. What was her initial frequency?

Two strings are adjusted to vibrate at exactly 240 Hz. Then the tension in one string is increased slightly. Afterward, three beats per second are heard when the strings vibrate at the same time. What is the new frequency of the string that was tightened?

A fighter jet is coming straight at you and speeding up. Likely it is above you, so you should be safe. Describe how the sound wave from the fighter jet is changing in this situation. Use the words pitch, doppler, frequency, intensity, subsonic, and supersonic.

you know the distance between the road centerline (source of traffic noise) and receiver was 10m after scattered trees and Hight of receiver was 2m, Then the distance adjustment .........factor equal 2.641 m 2.061m 2.146 m

A concert loudspeaker suspended high off the ground emits 29.0 W of sound power. A small microphone with a 0.700 cm² area is 53.0 m from the speaker. What is the sound intensity at the position of the microphone?▸ View Available Hint(s) Value How much sound energy impinges on the microphone each second?

An avant-garde composer wants to use the Doppler effect in his new opera. As the soprano sings, he wants a large bat to fly toward her from the back of the stage. The bat will be outfitted with a microphone to pick up the singer's voice and a loudspeaker to rebroadcast the sound toward the audience. The composer wants the sound the audience hears from the bat to be, in musical terms, one half-step higher in frequency than the note they are hearing from the singer. Two notes a half-step apart have a frequency ratio of 21/12= 1.059. With what speed must the bat fly toward the singer?

A source emitting a sinusoidal sound wave of frequency 360 Hz travels towards a wall at a speed 30 m/s. What is the beat frequency perceived by an observer moving at speed 10 m/s, speed of sound in air is 330 m/s ? A. 64Hz if observer is going away from the source and wall. B. 68 Hz if observer is going towards the source and the wall C. 60 Hz if observer is in between the wall and the source and moving away from the wall. D. 24 Hz if observer is in between the wall and the source, and moving towards the wall.

On a hot summer day, the temperature of air in Arizona reaches 108°F. What is the speed of sound in air at this temperature? (The speed of sound at 0°C is 331 m/s. Use the conversion 0°C = 273 K as necessary.)

An opera singer in a convertible sings a note at 600 Hz while cruising down the highway at 90 km/hr. What is the frequency heard by a person standing beside the road in front of the car? What is the frequency heard by a person on the ground behind the car?

The sun emits electromagnetic waves with a power of 4.0 x 1026 W. Determine the intensity of electromagnetic waves from the sun just outside the atmospheres of Venus. Determine the intensity of electromagnetic waves from the sun just outside the atmospheres of the earth.

A dolphin located in sea water at a temperature of 25°C emits a sound directed toward the bottom of the ocean 235 m below. How much time passes before it hears an echo?

A loudspeaker at the origin emits a 120 Hz tone on a day when the speed of sound is 340 m/s. The phase difference between two points on the x-axis is 5.9 rad. What is the distance between these two points?

A hammer taps on the end of a 5.0-m-long metal bar at room temperature. A microphone at the other end of the bar picks up two pulses of sound, one that travels through the metal and one that travels through the air. The pulses are separated in time by 9.00 ms. What is the speed of sound in this metal?

A bat locates insects by emitting ultrasonic "chirps" and then listening for echoes from the bugs. Suppose a bat chirp has a frequency of 25 kHz. In what direction would the bat have to fly for you to just barely be able to hear the chirp at 20 kHz? ▸ away from you toward you in another direction How fast would the bat have to fly for you to just barely be able to hear the chirp at 20kHz?

Choose the CORRECT alternative regarding loudness and pitch of sound: Loudness is determined by the amplitude of sound and pitch by the frequency of sound. Loudness is determined by the frequency of sound and pitch by the amplitude of sound. Both loudness and pitch of sound is determined by the amplitude of sound. Both loudness and pitch of sound is determined by the frequency of sound.

The longest pipe found in most medium-size pipe organs is 5.20 m (17.1 ft) long. You may want to review (Page). For related problem-solving tips and strategies, you may want to view a Video Tutor Solution of A tale of two pipes. What is the frequency of the note corresponding to the fundamental mode if the pipe is open at both ends?

A metal bar with a length of 1.00 m has a density of 6900 kg/m³. Longitudinal sound waves travel from one end of the bar to the other in a time interval of 4.40x10-4 s What is Young's modulus for this metal?

A 220 g mass attached to a horizontal spring oscillates at a frequency of 1.30 Hz. At t = 0s, the mass is at z = 4.80 cm and has v₂ = -32.0 cm/s. Determine the period. Express your answer to three significant figures and include the appropriate units.

An intensity of 1.0 W/m² is often used as the "threshold of pain". How much closer to the source can you move before the sound intensity reaches this threshold? Express your answer using two significant figures.

A 5.02-m, 0.736-kg wire is used to support two uniform 239- N posts of equal length . Assume that the wire is essentially horizontal and that the speed of sound is 344 m/s. A strong wind is blowing, causing the wire to vibrate in its 5th overtone. What is the frequency of the sound this wire produces?

A stationary police car emits a sound of frequency 1200 Hz that bounces off of a car on the highway and returns with a frequency of 1280 Hz. The police car is right next to the highway, so the moving car is traveling directly toward or away from it. Was the moving car moving towards or away from the police?

While sitting in your car by the side of a country road, you see your friend, who happens to have an identical car with an identical horn, approaching you. You blow your horn, which has a frequency of 260 Hz; your friend begins to blow his horn as well, and you hear a beat frequency of 6.2 Hz. How fast is your friend approaching you? Express your answer to two significant figures and include the appropriate units.

While traveling down the road at 55 mph, you pass a fire station where the siren is blowing. Which of the following observations is attributable to the Doppler Effect? Select one: a. The pitch of the siren changes as you approach the fire station. b. The loudness of the siren increases as you get closer to the fire station. c. The fire station gets larger as you approach it. d. The siren's pitch and volume remain constant.

A platinum wire that is 1.20 m long has a radius of 0.500 mm and is fixed at both ends. In its third harmonic it vibrates at 512 Hz. What is the speed of wave along the wire?

A police siren has a frequency of 550 Hz as the police car approaches you, 450 Hz after it has passed you and is receding. How fast are the police traveling? Assume the speed of sound is 343 m/s.

If a submarine's sonar can measure echo times with a precision of 0.0104 s, what is the smallest difference in distances in meters it can detect? Assume the speed of sound in the water is 1540 m/s.

How long must a flute be in order to have a fundamental frequency of 262 Hz (this frequency corresponds to middle C on the evenly tempered chromatic scale on a day when a temperature is 20.4°C? It is open at both ends. The speed of sound when the temperature is 0°C is 331 m/s. Give your answer in centimeters.