2.5 Wave Motion and Sound (Lvl 2)

Question 1

What is a mechanical wave?

Answer 1

An oscillation of matter.

Question 2

What are types of mechanical waves?

Answer 2

Sound waves
Slinky Waves
Water Waves.

Question 3

What does a mechanical wave require to transmit energy?

Answer 3

A medium.

Question 4

What type of medium does sound waves require?

Answer 4

Air molecules.

Question 5

What type of medium does Slinky wave require?

Answer 5

A slinky.

Question 6

What type of medium does ocean waves require?

Answer 6

Water.

Question 7

Where can’t mechanical waves exist?

Answer 7

In a vacuum.

Question 8

What can mechanical waves be classified as?

Answer 8

Transverse or longitudinal, depending on how they travel.

Question 9

What is a transverse wave?

Answer 9

Where it causes the medium to vibrate at a 90 degree angle to the direction of the wave.

Question 10

What is the highest point of the wave called?

Answer 10

Crest

Question 11

What is the lowest point of the wave called?

Answer 11

Trough

Question 12

What is a longitudinal wave?

Answer 12

Displacement of the medium that is parallel to the propagation of the wave.

Question 13

What is it called when the particles travelling through a wave are close to together?

Answer 13

Compression.

Question 14

What is it called when the particles travelling through a wave are spread apart?

Answer 14

Rarefaction (Expansion).

Question 15

What is an example of longitudinal waves?

Answer 15

Sound Waves.

Question 16

What is an example of a transverse waves?

Answer 16

Water waves.

Question 17

What are the characteristics of a sine wave?

Answer 17

Repeats itself at stand intervals with a constant amplitude.

Question 18

What is amplitude?

Answer 18

Is the greatest displacement from the rest point.

Question 19

What is wavelength?

Answer 19

Is the distance from one point on the wave pattern to the next point in a similar position (Peak to Peak).

Question 20

What is periodic time?

Answer 20

The time taken to complete 1 oscillation.

Question 21

what is frequency?

Answer 21

The number of complete oscillations in one second.

Question 22

What is wave interference phenomena?

Answer 22

Where two waves meet whilst travelling along the same medium and form a wave of greater, lower or the same amplitude.

It causes the medium to take on a shape the results from the net effect of two individual waves.

Question 23

What is a standing wave also known as?

Answer 23

A stationary wave.

Question 24

What is the wider definition of sound?

Answer 24

Sounds that include low and high frequency vibrations in air that cannot be heard by humans, and vibrations that travel through all forms of matter (Gas, Liquid and Solids).

Question 25

What does the speed of which sound waves travel at depend on?

Answer 25

The medium that the waves pass through.

Question 26

What is the speed of sound, when air is at room temperature?

Answer 26

Approx. 343m/s.

Question 27

What is the speed of sound, when in water?

Answer 27

Approx. 1500m/s.

Question 28

What is the speed of sound, when through a bar of steel?

Answer 28

Approx. 5000m/s

Question 29

Why is it important to consider the speed of sound in terms of the aerodynamics of an aircraft?

Answer 29

Because it is the point at which the air becomes increasingly compressible and the flying characteristics change drastically.

Question 30

What is the equation for the speed of sound?

Answer 30

c = 20 x SqRoot of T ``` c = Speed of sound in air (m/s) T = Temperature (Kelvin). ```

Question 31

What is Mach Number?

Answer 31

It describes the ratio of the speed of an aircraft in relation to the speed of sound.

Question 32

What is the equation for Mach number?

Answer 32

M = v/c ``` M = Mach number v = speed of object (m/s) c = speed of sound(m/s). ```

Question 33

How is sound produced?

Answer 33

It is normally a result of a mechanical disturbance on an object causing it to vibrate.

Question 34

What does the loudness of sound depend on?

Answer 34

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

Question 35

Where can sound not be transmitted?

Answer 35

Through a vacuum.

Question 36

How are sound waves propagated?

Answer 36

Longitudinal Waves.

Question 37

What will air have as a result of its density?

Answer 37

Low density = Rarefaction | High density = Compression.

Question 38

In sound, what is the result of a higher amplitude?

Answer 38

Louder sound.

Question 39

At what decibel can cause permanent damage to a persons hearing?

Answer 39

85dB.

Question 40

At what decibel can cause serious pain and permanent damage to a persons hearing?

Answer 40

130dB.

Question 41

What does pitch of a sound depend on?

Answer 41

The frequency of sound | ie. higher frequency, higher pitch and vice versa.

Question 42

What characteristic of sound enables humans to distinguish between the voices of men and women?

Answer 42

The pitch.

Question 43

What is pitch of a tone proportional to?

Answer 43

The number of compressions and rarefactions received per second, which is determined by the vibration frequency of the sound source.

Question 44

The property of sound, Quality, is used to do what?

Answer 44

To distinguish between 2 sounds of the same pitch and loudness, ie, sounds originating from 2 different musical instruments.

Question 45

What is tone of the lowest frequency called?

Answer 45

Fundamental frequency.

Question 46

When a fundamental frequency is determined, what are the other tones known as?

Answer 46

Overtones or harmonics.

Question 47

What are the 3 characteristics of sound?

Answer 47

1. Loudness 2. Pitch 3. Quality.

Question 48

What is the doppler effect?

Answer 48

Describes the change of frequency of a wave caused by the movement of a body relative to the wave source.

Question 49

In simpler terms, what is the doppler effect?

Answer 49

The ear hears a higher frequency as the source and observer approach each other, The ear hears a lower frequency when the source and observer recede from each other.

Question 50

When may the doppler effect be used in aircraft systems?

Answer 50

Detecting weather by measuring the motion of rain droplets and intensity of precipitation.