College Physics: Reasoning and Relationships

Nicholas J. Giordano

Chapter 13

Sound - all with Video Answers

Educators

Section 1

Sound Is a Longitudinal Wave

Problem 1

A sound wave in air has a frequency of $220 \mathrm{Hz}$. What is its wavelength?

Mirza Aslam Beig

Mirza Aslam Beig

Numerade Educator

Problem 2

The distance along a sound wave between a point of condensation and the nearest rarefaction is $0.45 \mathrm{m} .$ What is the wavelength of this sound wave?

Mirza Aslam Beig

Mirza Aslam Beig

Numerade Educator

Problem 3

Consider a sound wave in air with a frequency of $440 \mathrm{Hz}$. What is the distance between a region of condensation and an adjacent region of rarefaction?

Mirza Aslam Beig

Mirza Aslam Beig

Numerade Educator

Problem 4

Suppose a sound wave in air at room temperature has a wavelength of $400 \mathrm{m}$. What is its frequency?

Shoukat Ali

Other Schools

Problem 5

Two ships are traveling on a very dark and foggy night and cannot see each other, even though they have their lights on. They therefore use their foghorns to broadcast their presence. If the ships are 50 m apart, how long does it take the sound from one ship to reach the other?

Pronoy Sinha

Numerade Educator

Problem 6

A battleship is using sonar (reflected underwater sound signals) to detect the presence of nearby submarines. It is found that a sonar reflection has a round-trip travel time (from the battleship to the submarine and back) of 17 s. How far away from the battleship is the submarine?

Mirza Aslam Beig

Mirza Aslam Beig

Numerade Educator

Problem 7

A sound wave in an unknown gas has a frequency of $440 \mathrm{Hz}$ and a wavelength of $2.2 \mathrm{m}$. What type of gas might it be? Hint: Use Table 13.1

Mirza Aslam Beig

Mirza Aslam Beig

Numerade Educator

Problem 8

Consider two sounds of frequency $300 \mathrm{Hz}$, one traveling in carbon dioxide gas and the other in hydrogen gas. What is the ratio of the wavelengths in the two cases?

Mirza Aslam Beig

Mirza Aslam Beig

Numerade Educator

Problem 9

The lowest note on a piano has a fundamental frequency of about 27 Hz. What is the wavelength of this sound in air?

Mirza Aslam Beig

Mirza Aslam Beig

Numerade Educator

Problem 10

The ultrasonic sound waves used by owls for echolocation typically have a frequency of approximately $100 \mathrm{kHz}$. What is the wavelength of a sound with this frequency?

Mirza Aslam Beig

Mirza Aslam Beig

Numerade Educator

Problem 11

Consider a sound wave of frequency $f$ generated in air by a loudspeaker. When this sound wave reaches a nearby lake, the sound wave propagates into the water, where it has the same frequency f. What is the ratio of the wavelength of the wave in the water to the wavelength in air?

Mirza Aslam Beig

Mirza Aslam Beig

Numerade Educator

Problem 12

An automobile wheel of diameter $0.50 \mathrm{m}$ is found to emit sound with a frequency of $10 \mathrm{Hz}$. What is the automobile's speed? Hint: Assume the frequency of the emitted sound is equal to the rotation frequency of the wheel.

Mirza Aslam Beig

Mirza Aslam Beig

Numerade Educator

Problem 13

In western movies, the hero sometimes detects an approaching train by "listening" to the railroad tracks. If the tracks are made of steel, how many times faster does sound travel in the tracks than in air?

Mirza Aslam Beig

Mirza Aslam Beig

Numerade Educator