Physics Unit 4 -Sound and Waves B.

Question 1

Fixed End Reflection

Wave pulses

Answer 1

Wave pulses relfecting from a fixed end reflect INVERTED with the SAME amplitude

Question 2

Free End Reflection

Answer 2

Wave pulses reflecting from a free end reflect UNCHANGED with SAME amplitude

Question 3

2 Rules when moving wave pulse from one substance to another

Answer 3

1. Some energy from original wave pulse is TRANSMITTED
2. Some energy from original wave pulse is REFLECTED

Question 4

What does the amount and type of reflection depend on (When going from one substance to another?)

Answer 4

Difference in density

Question 5

When a wave pulse is going from a Faster to a Slower medium (Low -> High) how do the reflected and transmitted pulses change?

Answer 5

Reflected: Inverted w/ smaller amplitude
Transmitted: unaffected, reduced amplitude

Question 6

When a wave pulse is moving from a fast to slow medium, why the amplitude reduced?

Answer 6

b/c in a dense medium, it is difficult for particles to move to more dense mediums

Question 7

Wave Intereference

Answer 7

Two waves meet at a particular point and interfere with each other

Question 8

Principle of superposition

Answer 8

Individual amplitudes added together to form a resultant wave

Question 9

What happens after a resultant wave is made?

Answer 9

Waves just past through, undisturbed

Question 10

Constructive intereference

Answer 10

two crests/ two troughs that meet amplifying each other (Made into one BIG wave)

Question 11

Destructive Intereference

Answer 11

Crests and troughs of the same amplitude meet and dimish each other creating a node

Question 12

node

Answer 12

point of zero amplitude (waves cancel each other out)

Question 13

Sound is a __________________ wave made by regular _______________ and ______________ of matter

Answer 13

longitudinal; compression; rarefraction

Question 14

Sound particles of medium ____________ but DO NOT _________ with wave energy

Answer 14

vibrate ; travel

Question 15

Sound waves travels __________ from _________.

Answer 15

AWAY; source

Question 16

SOunds waves are represented as ______________ waves of air _________

Answer 16

transverse; pressure

Question 17

Sound waves must travel through a __________ in order to transmit sound

Answer 17

medium

Question 18

Pitch is the ______________ of sound

Answer 18

frequency

Question 19

Loudness is the __________________ of sound waves

Answer 19

amplitude

Question 20

Quality is the __________________ of sound waves

Answer 20

complexity

Question 21

Most efficient way of transfering sound is through a ? Why?

Answer 21

Solid; particles are close
IMF bonds act as a spring and sound transfers more efficiently

Question 22

As temperature rises, what happens to the molecules which affect the speed of sound?

Answer 22

Molecules move faster, allowing waves to be transmitted faster

Question 23

Explain how a Sonic Bomb is made

Answer 23

Sound pressure waves are left behind = cone shaped shock wave. There is a sudden pressure on the edge of the shock wave emitting a SONIC BOMB that is heard on the ground

Question 24

Mach < 1

Answer 24

Subsonic speed

Question 25

Mach =1

Answer 25

Speed of Sound

Question 26

Mach > 1

Answer 26

Supersonic Speed

Question 27

Doppler Effect

Answer 27

When soure moves, the frequency of it approaching is heard higher than the frquency of the source leaving Approaching = - Leaving = +

Question 28

Standing Waves

Answer 28

produced by interference of 2 waves with the same frequency and wavelength moving in opposite directions

Question 29

What happens when a tube has the same length, but a different frequency?

Answer 29

The next standing wave pattern will be present when frequency is changed

Question 30

Trumpet has what kind of standing wave?

Answer 30

Open-end air column

Question 31

Clarinet has what kind of standing wave?

Answer 31

closed-end air column

Question 32

How does the rich note of wind intruements happen?

Answer 32

Due to the superposition of different harmonics

Question 33

Mechanical Resonance and examples

Answer 33

A vibrating object gradually transfering energy to another object when the natural frequency of the second object matches the vibrational frequency of the original vibrating object. (Lithotripsy, breaking glass with voice)

Question 34

Damping

Answer 34

The reduction of the amplitude of a vibration due to the energy absorption or destructive intereference

Question 35

20Hz >

Answer 35

Infrasonic

Question 36

20Hz-20 000Hz

Answer 36

Audible

Question 37

20 000Hz <

Answer 37

Ultrasonic

Question 38

Explain Active Sound Cancellation

Answer 38

Microphone detects unwanted sound, device creates a inverted wave with the same amplitude inverted wave destructively interferes with the original wave creating a continous node