physics chapter 10

A railroad locomotive is at rest with its whistle shrieking, and then it starts moving toward you. Does the frequency that you hear increase, decrease, or stay the same?

The frequency increases

How about the wavelength reaching your ear?

The wavelength decreases.

How about the speed of sound in the air between you and the locomotive?

The speed is unchanged.

A tuning fork produces a sound with a frequency of 256 Hz and a wavelength in air of 1.33 m. Find the speed of sound in the vicinity of the fork.

…

The highest frequency sound humans can hear is about 20,000 Hz.

What is the wavelength of sound in air at this frequency?

What is the wavelength of the lowest sounds we can hear, about 20 Hz?

λ = 1.7 cm λ = 17 m

Knowing that the speed of sound in seawater is 1530 m/s, find the wavelength of a T wave.

λ = 219 m

A pendulum swings to and fro every 2.6 s . Find its frequency of swing.

f = 0.38 Hz

Find a wave speed of a certain 1.1-m-long wave with a frequency of 2.5 Hz .

v = 2.8 ms

A wiggle in time is a

vibration

A wave is a vibration in

-space. -time. -*both

When we consider how frequently a pendulum swings to and fro we’re talking about its

frequency

When we consider the time taken for a pendulum to swing to and fro we’re talking about the pendulum’s

period

A wave having a frequency of 1000 Hz vibrates at

1000 cycles per second.

How many vibrations per second are associated with a 101-MHz radio wave?

101,000,000

If the frequency of a certain wave is 10 Hz, its period is

.1 S

A 60 vibration per second wave travels 30 m in 1 s. Its frequency is

60 Hz and it travels at 30 m/s.

In Europe an electric razor completes 50 vibrations in 1 s. The frequency of these vibrations is

50 Hz with a period of 1/50 s.

A mass on the end of a spring bobs up and down 1 complete cycle every 2 s. Its frequency is

.5 Hz

The frequency of the second hand on a clock is

1/60 Hz.

The period of the second hand on a clock is

60 s

A weight suspended from a spring bobs up and down one complete cycle every 2 s. Its frequency is

.5 Hz

A weight suspended from a spring bobs up and down one complete cycle every 2 s. Its period is

2 s

If you double the frequency of a vibrating object, its period

is half

The pendulum with the greatest frequency has the

-shortest period. -shortest length. -*both

When a pendulum clock at sea level is placed at the top of a high mountain, it will

lose time.

A child swings to and fro on a playground swing. If the child stands on the swing rather than sitting on it, the time for a to-and-fro swing is

shortened

The source of all wave motion is a

vibrating object

What moves from place to place in wave motion is

energy

The medium in which a wave travels

transmits the wave

A wave travels an average distance of 6 m in 1 s. What is the wave’s velocity?

6 m/s

A wave oscillates up and down two complete cycles each 1 s. If the wave travels an average distance of 6 m in 1 s, its wavelength is

3 m

A floating leaf oscillates up and down two complete cycles each 1 s as a water wave passes by. What is the wave’s frequency?

2 Hz

A floating leaf oscillates up and down 2 complete cycles in 1 s as a water wave of wavelength 10 m passes by. What is the wave’s speed?

20 m/s

You dip your finger repeatedly into water and make waves. If you dip your finger more frequently, the wavelength of the waves

shortens

During a single period, the distance traveled by a wave is

one wavelength.

Radio waves travel at the speed of light, 300,000 km/s. The wavelength of a radio wave received at 100 MHz is

3.0 m

As a train of water waves goes by, a piece of cork floating on the water bobs up and down one complete cycle each second. The waves are 2 m long. What is the speed of the wave?

2 m/s

A skipper on a boat notices wave crests passing the anchor chain every 5 s. The skipper estimates the distance between crests is 15 m. What is the speed of the water waves?

3 m/s

A boat at anchor is rocked by waves whose crests are 40 m apart and with wave speed 10 m/s. These waves reach the boat once every

4.0 s

A wave travels an average distance of 1 m in 1 s with a frequency of 1 Hz. Its amplitude is

not enough information

In a longitudinal wave, the compressions and rarefactions travel in

the same direction.

Which of the following is not a transverse wave?

sound

Which of the following is a longitudinal wave?

sound

The vibrations of a transverse wave move in a direction

at right angles to the direction of wave travel.

The vibrations of a longitudinal wave move in a direction

along the direction of wave travel.

A sound wave is a

longitudinal wave.

Compressions and rarefactions are characteristic of

longitudinal waves

Compressions and rarefactions normally travel

in the same direction in a wave.

A compression is a squash and a rarefaction is a

stretch

The source of all sounds is something that is

vibrating

A sound source of high frequency emits a high

pitch

Double the frequency of sound and you also double its

none of the above

The range of human hearing is about

20 Hz – 20,000 Hz.

Sound waves cannot travel in

a vacuum

The speed of a sound wave in air depends on

the air temperature.

Sound travels faster when the air is

warm

A 340-Hz sound wave travels at 340 m/s in air with a wavelength of

1 m

Sound travels fastest in

ice

An explosion occurs 34 km away. For sound that travels at 340 m/s, you’ll hear the explosion in

more than 20 s.

A general rule for estimating the distance in kilometers between an observer and a lightning bolt is to count the number of seconds between seeing the lightning and hearing it, and dividing by

3

The reflection of sound is

an echo

Sound energy that is not reflected is

-transmitted. -absorbed. -*either or both

Reverberation is a phenomenon you would likely to hear if you sing in the

shower

Reverberation is a case of

re-echoed sound.

The explanation for all types of refraction involves a change in

speed

Refraction of sound can occur in

-water. -air. -*both

When sound travels faster at ground level than higher in the air, sound tends to bend

upward

When sound travels faster higher above ground level than it does closer to the ground, sound bends

downward

On days when the air nearest the ground is colder than air above, sound waves

tend to be refracted downward.

A dolphin perceives its environment by the sense of

-sound. -sight. -*both

In designing a music hall, an acoustical engineer is concerned with

wave interference.

While at a concert, a wind blows directly from the orchestra toward you. The speed of the sound you hear is

increased

A bat chirps to locate a tasty lunch. The chirp travels at 340 m/s and its echo is heard 1 s after the chirp. Distance to the lunch is

340 m

Ultrasonic sound that travels at 1530 m/s in ocean water is bounced off the ocean floor and returns to the ship above. If the round trip takes 3 s, the depth of the water is

2295 m

The natural frequency of an object depends on its

-size and shape. -elasticity. -*both

The object with the natural frequency of higher pitch is a

small bell

The least amount of energy is required to produce forced vibration in an object

at its natural frequency.

Resonance occurs when a 200-Hz tuning fork encounters a sound wave with a frequency of

200 Hz

A bass fiddle is louder than a harp because of its

sounding board

When the handle of a tuning fork is held solidly against a table, the sound becomes louder and the time the fork keeps vibrating becomes

shorter

Some singers are able to shatter a crystal chandelier with their voice, which illustrates

resonance

Troops break step when marching across a bridge to prevent

resonance

Wave interference occurs for

-light waves. -sound waves. -water waves. -*all of the above

A standing wave occurs when

a wave reflects upon itself

A node is a position of

minimum amplitude

Sound waves can interfere with one another so that no sound is produced.

true

The phenomenon of beats results from sound

interference

When you tune a radio to a certain station, you match the frequency of the internal electrical circuit to the frequency of that radio station, which illustrates

resonance

What beat frequency is produced when a 240-Hz and a 246-Hz tuning fork are sounded together?

6 Hz

Suppose you sound a 1056-Hz tuning fork when you strike a note on the piano and hear 2 beats/second. You tighten the piano string very slightly and now hear 3 beats/second. What is the frequency of the piano string?

1059 Hz

Two tuning forks produce sounds of wavelengths 3.4 m and 3.3 m. What beat frequency is produced?

3.0 Hz

The Doppler effect is characteristic of

-sound waves. -water waves. -light waves. -*all of the above

A Doppler effect occurs when a source of sound moves

-toward you. -away from you. -*either

A Doppler effect occurs when a source of sound moves

toward you

For light, a red shift indicates the light source moves

away from you

In perceiving its environment, a dolphin makes use of

-ultrasound. -the Doppler effect. -echoes. -*all of the above

Which doesn’t belong to the same family?

radio waves

A wave barrier is produced in water when the speed of an object

matches the speed of waves in water.

A bow wave is produced in water when the speed of an object

exceeds the speed of waves in water.

A shock wave is produced when the speed of an object

exceeds the speed of sound in air.

A sonic boom can NOT be produced by

an aircraft flying slower than the speed of sound.

The pitch of a musical sound depends on the sound wave’s

frequency

The loudness of a musical sound is a measure of the sound wave’s

amplitude

The quality of a musical note has to do with its

harmonics

High pitched sound has a high

frequency

The fundamental frequency of a violin string is 440 Hz. The frequency of its second harmonic is

880 Hz.

The amplitude of a sound wave is closely related to

loudness

All other things being the same, strings having more mass than other strings will produce

lower frequency notes.

Repeatedly tap the side of a drinking glass with a spoon while filling it with water and you will notice that the pitch of the sound

decreases

Does the conical angle of a shock wave open wider, narrow down, or remain constant as a supersonic aircraft increases its speed?

The conical angle of a shock wave becomes narrower with greater speeds.