2.5 Wave Motion And Sound

Question 1

What is a mechanical wave?

Answer 1

An oscillation of matter

Question 2

Why is a mechanical wave an oscillation of matter?

Answer 2

It requires a medium through which to transmit energy

Question 3

Why cant mechanical waves exist in a vacuum?

Answer 3

Because vacuums have no matter to transmit energy through

Question 4

What are the two classifications of mechanical waves?

Answer 4

Transverse or longitudinal

Question 5

How does a transverse wave travel along its wavelength?

Answer 5

Perpendicular to the direction of propagation of the wave (up and down like a normal wavelength)

Question 6

How does a longitudinal wave travel along its wavelength?

Answer 6

The displacement is parallel to the propagation of the wave (being pushed horizontally)

Question 7

What are the 4 parts to a transverse wave?

Answer 7

-wavelength
-amplitude
-crest (top)
-trough (bottom)

Question 8

In a longitudinal wave what is it called when the particles are close together when traveling through?

Answer 8

Compression

Question 9

In a longitudinal wave what is it called when the particles are spread apart and travel through the wave?

Answer 9

Rarefaction (sometimes called expansion)

Question 10

What is one periodic time of a wavelength?

Answer 10

The time it takes to complete one oscillation

Question 11

What is the frequency of a wavelength?

Answer 11

The number of complete oscillations in one second

Question 12

What is the equation for wavelength?

Answer 12

Wave speed / frequency

Question 13

What is wave interference?

Answer 13

The phenomenon that occurs when two waves meet and form a resultant wave greater, lower, or the same amplitude

Question 14

What are standing/ stationary waves?

Answer 14

The combination of waves of the same amplitude and frequency moving in opposite directions casing a point where the wave doesn’t move at all

Question 15

The phenomenon of standing/stationary waves is the result of?

Answer 15

Interference

Question 16

What are sound waves?

Answer 16

Vibrations that travel through the air or another medium and can be detected when they reach an elastic medium, such as a microphone or eardrum

Question 17

The speed at which sound waves travel depends on?

Answer 17

The medium that the waves are passing throgh

Question 18

What is the speed of sound in a normal room?

Answer 18

343m/s

Question 19

What is the speed of sound in water?

Answer 19

1500m/s

Question 20

When temperature increase wha happens to the speed of sound?

Answer 20

It decreases

Question 21

What is the equation to calculate the speed of sound?

Answer 21

20 x √temperature

Question 22

What is a mach number describing?

Answer 22

The ratio of the speed of an aircraft in relation to the speed of sound

Question 23

What is subsonic?

Answer 23

Less than mach 1

Question 24

What is transonic?

Answer 24

Going mach 1

Question 25

What is supersonic?

Answer 25

Greater than mach 1

Question 26

What is hypersonic?

Answer 26

Faster than mach 5

Question 27

What does the loudness of a sound depend on?

Answer 27

The amplitude of the vibrations and the distance from the sound source

Question 28

At what level of noise causes permanent damage to human ear from a prolonged exposure?

Answer 28

Sound pressure levels exceeding 85dB

Question 29

In relation to sound what is pitch?

Answer 29

A shrill (high pitched noise) sound can be distinguished from a deep sound

Question 30

What does pitch depend on?

Answer 30

The frequency (the greater the frequency, the higher the pitch and vice versa)

Question 31

When you have multiple sounds being produced what is the tone with the lowest frequency called?

Answer 31

Fundamental frequency

Question 32

When you have multiple sounds playing what are the tones called if they aren’t the lowest frequency?

Answer 32

Overtones or harmonics

Question 33

What is the Doppler effect?

Answer 33

The change in frequency of a wave, caused by the movement of a body relative to the wave source (think of an ambulance driving past and how the sound changes)

Question 34

If the source of a sound moves towards you, what happens to the frequency of the sound?

Answer 34

It will appear higher and faster

Question 35

If the source of a sound moves away from you, what happens to the frequency of the sound?

Answer 35

It appears lower and slower