FINALS- UNIT 2

Question 1

Complex Waves

Answer 1

Combo of two or more pure tones of different frequencies

Question 2

Reinforcement Interference

Answer 2

Also known as constructive interference

When two waves are exactly 0° out of phase

wave is twice the amplitude

Question 3

Cancellation Interference

Answer 3

Also known as Destructive Interference

When two waves are exactly 180° out of phase

combined amplitude is zero

Question 5

Fundamental Frequency f₀

Answer 5

Lowest frequency component of a complex periodic wave

Question 6

Harmonic

Answer 6

Integer multiple of the fundamental frequency

Question 7

The _________ harmonic is the equivalent to the fundamental frequency

Answer 7

First Harmonic

Question 8

Waveform

Answer 8

Amplitude as a funciton of time

temporal waveform

Question 9

Spectrum

Answer 9

Graph of amplitude function of frequency

amplitude spectrum

Question 10

Fourier’s Theroem

Answer 10

Complex waves can be broken down into pure tones

Question 11

Square Wave

Answer 11

• Sum of odd harmonics (1, 3, 5, 7)
• amplitude decreases with increasing frequency
• sounds like clarinet

Question 12

Transients

Answer 12

brief abrupt sound

sounds like click or pop

Question 13

White random noise

Answer 13

many frequency components with same amp

Question 14

Filters: Four basic shapes of continuous spectrum

Answer 14

1. Flat Spectrum
2. High Pass filter
3. Low Pass filter
4. Band Pass filter

Question 15

Flat Spectrum

Answer 15

energy at all frequencies

Question 16

High Pass Filter

Answer 16

Filter that has energy at frequencies higher than some cut off frequency

Question 17

Low Pass Filter

Answer 17

Filter that has energy at frequencies lower than some cut off frequency

Question 18

Band Pass Filter

Answer 18

Filter that has energy at frequencies between two cut-off frequencies

Question 19

Standing Waves

Answer 19

Propagating & reflected waves interact to form a pattern on the string

*when reflected waves flip

• longest pattern that can occur, “first wave of vibration”
• Lowest possible vibration frequency for string (Fundamental Frequency)

Question 20

Node

Answer 20

Zero displacement on wave

Question 21

Antinode

Answer 21

Maximum displacement on wave

Question 22

As mode of vibration ___________, amplitude _______

Answer 22

Increase, decrease

Question 23

Tubes open at both ends

Answer 23

antinodes on end, nodes in center

called half wave-length resonators

λ = 2L

Question 24

Tubes open at one end

Answer 24

• Node at closed end, antinode at open
• First mode of vibration corresponds to 1/4
• λ = 4L
• Only at odd harmonics

Question 25

Tubes open at ____ end(s) are the model for the ear canal

Answer 25

one

Question 26

Immittance

Answer 26

General term that describes how well energy flows through system

• impedance
• admittance

Question 27

Impedance

Answer 27

dictates how much force must be applied to the mass to move it back and forth

Z = f/v

Question 28

Mass Reactance

Answer 28

component of impedance due to mass

X_m

increases with frequency

Question 29

Stiffness

Answer 29

X_{s opposes movement due to restoring force}

• opposes low frequency oscillations more than high
• X_s decreases with increasing frequency
• Stiff objects move more quickly

Question 30

Resistance

Answer 30

• Frequency independent
• Determines how long system will oscillate