We are open Saturday and Sunday!

Call Now to Set Up Tutoring:

(888) 888-0446

AP Physics 1 : Sound Waves

Study concepts, example questions & explanations for AP Physics 1

Create An Account

All AP Physics 1 Resources

7 Diagnostic Tests 170 Practice Tests Question of the Day Flashcards Learn by Concept

Example Questions

← Previous 1 2 Next →

Example Question #1 : Sound Waves

Alice measures the wavelength and frequency of a sound wave as

$\lambda=3.5m$

T=0.01s

At what speed is the sound traveling?

Possible Answers:

$0.00286\frac{m}{s}$

$28.6 \frac{m}{s}$

$350 \frac{m}{s}$

$427\frac{m}{s}$

$3.5\frac{m}{s}$

Correct answer:

$350 \frac{m}{s}$

Explanation:

We know from the question that

$\lambda=3.5m$

T=0.01s

Frequency is the inverse of period:

$f=\frac{1}{T}=\frac{1}{0.01s}=100s^{-1}}$

The velocity of a wave is its wavelength multiplied by its frequency:

$v=\lambda f = (3.5 m)(100s^{-1})=350\frac{m}{s}$

Report an Error

Example Question #2 : Sound Waves

You are standing on the sidewalk when a police car approaches you at $30\frac{m}{s}$ with its sirens on. Its sirens seem to have a frequency of 500 Hertz. After the police car passes you and is driving away, what will be the new frequency you hear?

$v_{sound\:in\:air}=340\frac{m}{s}$

Possible Answers:

507Hz

419 Hz

456Hz

544Hz

500Hz

Correct answer:

419 Hz

Explanation:

The doppler effect follows this formula:

$f=\frac{s}{s+v}f_0$

In this equation, is the new frequency you will hear, is the speed of sound, is the velocity of the moving sound-emitting thing, and f_0 is the initial frequency of the sound.

Plugging the given values in, we can describe the initial situation as:

$500=\frac{340}{340-30}f_0$

Note that the velocity is negative (-30) because the car is driving towards you.

Therefore,

$f_0=456s^{-1}$

When the police car is driving away, the situation is described with a positive velocity:

$f=\frac{340}{340+30}456$

Therefore,

$f=419s^{-1}$

Report an Error

Example Question #3 : Sound Waves

A guitar player uses beats to tune his instrument by playing two strings. If one vibrates at 550 Hz and the second at 555 Hz, how many beats will he hear per minute?

Possible Answers:

$\frac{1}{2} \textup{\textup{ bpm}}$

$50 \textup{\textup{ bpm}}$

$5 \textup{\textup{ bpm}}$

$300 \textup{\textup{ bpm}}$

$\frac{1}{12} \textup{\textup{ bpm}}$

Correct answer:

$300 \textup{\textup{ bpm}}$

Explanation:

Two waves will emit a beat with a fequency equal to the difference in frequency of the two waves. In this case the beat frequency is:

$555 - 550=5 \textup{\textup{ Hz}}$ (beats per second)

Convert to beats per minute:

$5 \textup{\textup{ Hz}}\times \frac{60}{1} \frac{seconds}{minutes} = 300 \textup{\textup{ bpm}}$

Report an Error

Example Question #4 : Sound Waves

The ukulele is a short instrument, relative to a guitar. How does this affect the frequencies of sounds that these two instruments produce? Assume the two instruments use the same strings.

Possible Answers:

The shorter length creates a lower speed of sound

The shorter length creates a higher speed of sound

The shorter length strings produce higher frequencies

The shorter length strings produce lower frequencies

Correct answer:

The shorter length strings produce higher frequencies

Explanation:

The speed of sound in air is constant, assuming that the temperature of the air is constant. When the length of the string is shortened, by the principles of standing waves, this creates a higher frequencies. Assuming that the two instruments use the same strings is equivalent to stating that the two instruments have strings of equal linear mass density. This situation represents a standing wave, thus we can relate the following equation for the first harmonic:

$L=2\lambda$

Where, is the length of the string and $\lambda$ is the wavelength. Then we can use the following equation to relate wavelength and speed (which is known) to frequency:

$v=\lambda f$

Since the velocity of sound in a fixed medium is constant, we see that a shorter length, corresponds to a shorter wavelength, $\lambda$ . Thus when $\lambda$ decreases, frequency, must increase, to keep velocity constant.

Report an Error

Example Question #5 : Sound Waves

A sound played from a speaker is heard at an intensity of 100W from a distance of 5m. When the distance from the speaker is doubled, what intensity sound will be heard?

Possible Answers:

200W

50W

400W

25W

Correct answer:

25W

Explanation:

Intensity is related to radius by the inverse square law:
$\frac{I_1}{I_2}=\frac{r_2^2}{r_1^2}$
This equation is derived from the concept that the energy from the sound waves is conserved and spread out over an area, producing the r^2 term. Applying this concept, when the radius doubles, the intensity decreases by a factor of 4. The correct answer is 25W .

Report an Error

Example Question #6 : Sound Waves

A stopped pipe (closed at both ends) sounds a frequency of 500Hz at its fundamental frequency. What is the length of the pipe?

$v_{sound}=345\frac{m}{s}$

Possible Answers:

58.90 cm

21.75 cm

17.25 cm

35.22 cm

Correct answer:

17.25 cm

Explanation:

L=0.1725m A stopped pipe can be modeled with the following equation:
$f_n=\frac{nv}{4L}$

Rearrange the equation to solve for L, then plug in given values and solve.

$L=\frac{nv}{4f_n}$

$L=\frac{1*345}{4*500}$

L=0.1725m=17.25cm

Report an Error

Example Question #7 : Sound Waves

What is the beat frequency between a 305Hz and a 307Hz sound?

Possible Answers:

93,635Hz

2Hz

0.993Hz

612Hz

Correct answer:

2Hz

Explanation:

Frequency of beats is determined by the absolute value of the difference between two different frequencies. Thus, the beats frequency is 2Hz. Note that beat frequency is always a positive number.

Report an Error

Example Question #8 : Sound Waves

An open pipe (open at both ends) has a fundamental frequency of 600Hz. How long is the pipe?

$v_{sound}=345\frac{m}{s}$

Possible Answers:

14.38cm

28.75cm

57.5cm

32.65cm

Correct answer:

28.75cm

Explanation:

An open pipe can be modeled by the following equation:

$f_n=\frac{nv}{2L}$

Rearrange the equation to solve for then plug in given values and solve.

$L=\frac{nv}{2f_n}$

$L=\frac{1*345}{2*600}$

L=0.2875m=28.25cm

Report an Error

Example Question #1 : Sound Waves

A student at a concert notices that a balloon near the large speakers moving slightly towards, then away from the speaker during the low-frequency passages. The student explains this phenomenon by noting that the waves of sound in air are __________ waves.

Possible Answers:

transverse

electromagnetic

torsional

longitudinal

latitudinal

Correct answer:

longitudinal

Explanation:

Sound is a longitudinal, or compression wave. A region of slightly more compressed air is followed by a region of slightly less compressed air (called a rarefaction). When the compressed air is behind the balloon, it pushes it forward, and when it is in front of the balloon, it pushes it back. This only works if the frequency is low, because the waves are long enough so that the balloon can react to them.

Report an Error

Example Question #10 : Sound Waves

Consider a 37cm long harp string with a fundamental frequency of 440Hz.

Calculate the speed of the standing wave created by plucking this string.

Possible Answers:

$325.6\frac{m}{s}$

$54.1\frac{m}{s}$

$440.0\frac{m}{s}$

$143.5\frac{m}{s}$

$215.7\frac{m}{s}$

Correct answer:

$325.6\frac{m}{s}$

Explanation:

Use the following equation to find the velocity of the wave, using its fundamental frequency and the length:

$f_1=\frac{v}{2L}$

$v=\frac{440}{2*0.37}=325.6\frac{m}{s}$

Report an Error

← Previous 1 2 Next →

View AP Physics 1 Tutors

Pankaj
Certified Tutor

University of Delhi, Electrical Engineer, Electrical Engineering. Columbia University in the City of New York, Master of Arts...

View AP Physics 1 Tutors

Shakeel
Certified Tutor

View AP Physics 1 Tutors

Clarke
Certified Tutor

University of Pittsburgh-Pittsburgh Campus, Bachelor of Science, Biological and Physical Sciences.

All AP Physics 1 Resources

7 Diagnostic Tests 170 Practice Tests Question of the Day Flashcards Learn by Concept

Popular Subjects

ACT Tutors in Seattle, MCAT Tutors in Phoenix, Biology Tutors in Philadelphia, Computer Science Tutors in Houston, GMAT Tutors in Los Angeles, Spanish Tutors in Philadelphia, Chemistry Tutors in San Diego, ACT Tutors in Houston, ACT Tutors in Atlanta, Physics Tutors in Washington DC

Popular Courses & Classes

LSAT Courses & Classes in Philadelphia, ACT Courses & Classes in Philadelphia, GRE Courses & Classes in Miami, GRE Courses & Classes in Dallas Fort Worth, MCAT Courses & Classes in Dallas Fort Worth, Spanish Courses & Classes in Miami, SAT Courses & Classes in San Diego, ACT Courses & Classes in New York City, ISEE Courses & Classes in San Francisco-Bay Area, GRE Courses & Classes in Atlanta

Popular Test Prep

ACT Test Prep in Dallas Fort Worth, ACT Test Prep in Philadelphia, GRE Test Prep in San Francisco-Bay Area, SSAT Test Prep in Seattle, LSAT Test Prep in Phoenix, MCAT Test Prep in Philadelphia, GMAT Test Prep in Dallas Fort Worth, GRE Test Prep in Washington DC, GRE Test Prep in New York City, SAT Test Prep in Boston

DMCA Complaint

If you believe that content available by means of the Website (as defined in our Terms of Service) infringes one or more of your copyrights, please notify us by providing a written notice (“Infringement Notice”) containing the information described below to the designated agent listed below. If Varsity Tutors takes action in response to an Infringement Notice, it will make a good faith attempt to contact the party that made such content available by means of the most recent email address, if any, provided by such party to Varsity Tutors.

Your Infringement Notice may be forwarded to the party that made the content available or to third parties such as ChillingEffects.org.

Please be advised that you will be liable for damages (including costs and attorneys’ fees) if you materially misrepresent that a product or activity is infringing your copyrights. Thus, if you are not sure content located on or linked-to by the Website infringes your copyright, you should consider first contacting an attorney.

Please follow these steps to file a notice:

You must include the following:

A physical or electronic signature of the copyright owner or a person authorized to act on their behalf; An identification of the copyright claimed to have been infringed; A description of the nature and exact location of the content that you claim to infringe your copyright, in \ sufficient detail to permit Varsity Tutors to find and positively identify that content; for example we require a link to the specific question (not just the name of the question) that contains the content and a description of which specific portion of the question – an image, a link, the text, etc – your complaint refers to; Your name, address, telephone number and email address; and A statement by you: (a) that you believe in good faith that the use of the content that you claim to infringe your copyright is not authorized by law, or by the copyright owner or such owner’s agent; (b) that all of the information contained in your Infringement Notice is accurate, and (c) under penalty of perjury, that you are either the copyright owner or a person authorized to act on their behalf.

Send your complaint to our designated agent at:

Charles Cohn Varsity Tutors LLC
101 S. Hanley Rd, Suite 300
St. Louis, MO 63105

Or fill out the form below:

Do not fill in this field

Contact Information

* Full legal name

Company name

* Phone number

* Email address

Address

* Address1

Address2

* City

* State

* Zipcode

* Country

Complaint Details

* URL of copyrighted work (where your original material is located)

* Please describe the copyrighted work so that it may be easily identified

I am the owner, or an agent authorized to act on behalf of the owner of an exclusive right that is allegedly infringed.

I have a good faith belief that the use of the material in the manner complained of is not authorized by the copyright owner, its agent, or the law.

This notification is accurate.

I acknowledge that there may be adverse legal consequences for making false or bad faith allegations of copyright infringement by using this process.

* Signature (your digital signature is legally binding)

HIGH SCHOOL

GRADUATE SCHOOL

K-8

Search 50+ Tests

math tutoring

science tutoring

foreign languages

elementary tutoring

other

Search 350+ Subjects

AP Physics 1 : Sound Waves

Study concepts, example questions & explanations for AP Physics 1

All AP Physics 1 Resources

Example Questions

Example Question #1 : Sound Waves

Example Question #2 : Sound Waves

Example Question #3 : Sound Waves

Example Question #4 : Sound Waves

Example Question #5 : Sound Waves

Example Question #6 : Sound Waves

Example Question #7 : Sound Waves

Example Question #8 : Sound Waves

Example Question #1 : Sound Waves

Example Question #10 : Sound Waves

All AP Physics 1 Resources

Report an issue with this question

DMCA Complaint

Contact Information

Address

Complaint Details

Email address:
Your name:
Feedback: