Chapter 25

Question 1

Who discovered that the time a pendulum takes to swing back and forth through small angles depends only on the length of the pendulum—the mass has no effect?

Answer 1

Galileo

Question 2

Period

Answer 2

The time of a back-and-forth swing of the pendulum

Question 3

What does the period of the pendulum depend on?

Answer 3

Only on the length of a pendulum and the acceleration of gravity

Question 4

4). Does a long pendulum have a longer period or does a shorter pedulum have a longer period.

Answer 4

long pendulum

Question 5

5). Why does a long pendulum have a longer period?

Answer 5

it swings back and forth more slowly—less frequently—than a short pendulum

Question 6

What is the back-and-forth vibratory motion (often called oscillatory motion) of a swinging pendulum called?

Answer 6

simple harmonic motion

Question 7

What is a sine curve?

Answer 7

a pictorial representation of a wave

Question 8

What is the source of all waves?

Answer 8

something that vibrates

Question 9

crests

Answer 9

the high points on a wave

Question 10

The low points on a wave are called..

Answer 10

troughs

Question 11

What does the term amplitude refer to?

Answer 11

the distance from the midpoint to the crest (or trough) of the wave

Question 12

What does the amplitude equal?

Answer 12

the maximum displacement from equilibrium

Question 13

What is the wavelength of a wave?

Answer 13

the distance from the top of one crest to the top of the next one/the distance between successive identical parts of the wave

Question 14

What are the wavelength at the beach measured in?

Answer 14

meters

Question 15

What are the wavelengths in the pond measured in?

Answer 15

centimeters

Question 16

What is an object’s frquency>

Answer 16

The number of vibrations an object makes in a unit of time

Question 17

A complete back-and-forth vibration is…

Answer 17

one cycle

Question 18

The frequency of the vibrating source and the frequency of the wave it produces are the same. T OR F

Answer 18

True

Question 19

The unit of frequency is called the…

Answer 19

hertz (Hz)

Question 20

A frequency of one cycle per second is _______, two cycles per second is _______.

Answer 20

1Hz; 2Hz

Question 21

Higher frequencies are measured in…

Answer 21

Kilohertz and/or Megahertz

Question 22

Formula for frequency and period

Answer 22

frequency = 1/period; period = 1/frequency

Question 23

How does most of the information around us get to us?

Answer 23

In some form of wave

Question 24

Sound is energy that…

Answer 24

travels to our ears in the form of a wave

Question 25

Light is energy that...

Answer 25

comes to our eyes in the form of a different kind of wave (an electromagnetic wave)

Question 26

When energy is transferred by a wave from a ___________source to a distant __________, there is no _________of matter between the two points.

Answer 26

vibrating; receiver; transfer

Question 27

When an end of the string is shaken, a rhythmic disturbance travels along the string, the _________that moves along the length of the string.

Answer 27

disturbance

Question 28

When a stone is dropped in a quiet pondm the disturbance moves and the water doesn't and the disturbance passes, where does the water end up?

Answer 28

right where it was before the wave passes

Question 29

When someone speaks to you from across the room, the disturbance in the air that travels across the room. Do the air molecules move?

Answer 29

No, they are the medium through which wave energy travels.

Question 30

The energy __________by a _____from a ___________source to a ________is carried by a __________in a ___________.

Answer 30

transferred; wave; vibrating; disturbance; receiver; mediu,

Question 31

What does the speed of a wave depend on?

Answer 31

the medium through which the wave moves

Question 32

Are the speed, wavelength, and frequency, no matter the medium, aslways related?

Answer 32

Yes

Question 33

You can calculate the speed of multiplying the...

Answer 33

wavelength by the frequency

Question 34

Long wavelengths have ______frequencies and short wavelengths have _________frequencies.

Answer 34

low; high

Question 35

Wavelength and frequency vary ________to produce the same wave speed for all sound.

Answer 35

inversely

Question 36

Transverse wave

Answer 36

Whenever the motion of the medium is at right angles to the direction in which a wave travels

Question 37

Waves in the stretched strings of musical instruments and the _____________aves that make up radio eaves and light are transverse.

Answer 37

electromagnetic

Question 38

Are all waves transverse?

Answer 38

No

Question 39

Sometimes the particles of the ________move back and forth in the ________direction in which the wave travels.

Answer 39

medium; same

Question 40

Longitudinal wave

Answer 40

When the particles oscillate parallel to or along the direction of the wave rather than at right angles to it

Question 41

What waves are longitudinal waves

Answer 41

sound waves

Question 42

How are transverse waves demonstrated in a slinky?

Answer 42

By shaking it up and down

Question 43

How are longitudinal waves demonstrated in a slinky?

Answer 43

By shaking the end in and out.

Question 44

Interference pattern

Answer 44

A regular arrangement of places where wave effects are increased, decreased, or neutralized.

Question 45

When do interfernce patterns occur?

Answer 45

When waves from different dources arrive at the same - at the same time

Question 46

Constructive Interference

Answer 46

the crest of one wave overlaps the crest of another and their individual effects add together

Question 47

What is the result of constructive interference?

Answer 47

A wave of increased amplitude (reinforcement)

Question 48

Destructive Interference

Answer 48

the crest of one wave overlaps the trough of another and their individual effects are reduced (cancellation)

Question 49

Where wave interference easiest to see?

Answer 49

In water

Question 50

What happens along the regions where waves cancel each other out>

Answer 50

The two objects arrive "out of step"/"out of phase"

Question 51

What happens when waves are "out of phase"

Answer 51

the crests of one wave overlap the troughs of another to produce regions of zero amplitude

Question 52

What happens when waves are "in phase"

Answer 52

the crests of one wave overlap the crests of the other, and the troughs overlap as well

Question 53

What is the moiré pattern is formed similar to?

Answer 53

the interference pattern of waves

Question 54

Is interference a characteristic of all wave motions?

Answer 54

Yes

Question 55

Standing wave

Answer 55

a wave that appears to stay in one place—it does not seem to move through the medium

Question 56

What are nodes?

Answer 56

the stationary points on a standing wave

Question 57

What are antinodes?

Answer 57

The positions on a standing wave with the largest amplitudes

Question 58

Where do antinodes occur?

Answer 58

halfways between nodes

Question 59

Standing waves are the result of interference. T or F

Answer 59

True

Question 60

When two waves of equal amplitude and wavelength pass through each other in opposite directions, the waves are...

Answer 60

always out of phase at the nodes

Question 61

How can you produce a variety of standing waves?

Answer 61

By shaking the rope at different frequencies

Question 62

A standing wave forms only if ________a wavelength or a __________of _______a wavelength fits exactly into the length of the _____________ __________.

Answer 62

half; multiple; half; vibrating medium

Question 63

If you increase the frequency, you...

Answer 63

increase the amount of interesting waves

Question 64

Can standing waves be produced in either transverse or longitudinal waves?

Answer 64

Yes

Question 65

Situation: bug is treading in water in a fixed position. what type of circle does the crests of its wave make?

Answer 65

concentric

Question 66

If the bug bobs in the water at a constant frequency, the distance between wave crests (wavelength) will be what for all successive waves? Is the frequency the same as well?

Answer 66

the same; the same

Question 67

What happens when the jiggling bug moves across the water at a speed less than the wave speed?

Answer 67

The bug chases part of the crests it has produced, the wave pattern is distorted and is no longer concentric.

Question 68

As a wave source approaches, an observer encounters waves with a ________frequency . As the wave source moves away, an observer encounters waves with a ________frequency

Answer 68

higher; lower

Question 69

Doppler effect

Answer 69

This apparent change in frequency due to the motion of the source (or receiver)

Question 70

Water waves spread over the ____________surface of the water

Answer 70

flat

Question 71

Sound and light waves, on the other hand, travel in ______________.

Answer 71

three-dimensional space in all directions like an expanding balloon.

Question 72

When the firetruck approaches, the pitch sounds higher than normal. Why?

Answer 72

This occurs because the sound wave crests are encountering you more frequently

Question 73

An increase in frequency in light is called...

Answer 73

a blue shift, bc the increase is toward the high-frequency, or blue, end of the color spectrum

Question 74

A decrease in frequency in light is called...

Answer 74

a red shift, bc the increase is toward the low-frequency, or red, end of the color spectrum

Question 75

A bow wave occurs when...

Answer 75

a wave source moves faster than the wave it produces.

Question 76

What is the shape of the bow wave

Answer 76

A v shape

Question 77

What is a shock wave?

Answer 77

a three-dimensional wave that consists of overlapping spheres that form a cone

Question 78

When does a shock wave occur?

Answer 78

When an object moves faster than the speed of sound

Question 79

When do we hear a sonic boom on an aircraft?

Answer 79

Only when the craft moves faster than sound do the crests overlap and encounter the listener in a single burst