Lecture 1 (1/23) Flashcards
Sound is what kind of movement?
Vibration
Is sound a form of energy?
Yes
Sound cannot exist without
Medium
A medium must have what 2 components?
- Mass
- Elasticity
Define mass
The amount of matter
What is typically the medium?
air
Is mass the same as weight?
No
define density
mass per unit volume
Which is more dense? 4 air molecules in a container or 4 million air molecules in a container?
4 million
Define elasticity
When something can recover from distortion
How is elasticity measured?
Stiffness or Compliance
Stiffness and compliance are
Inversely proportional
more compliant is ____ stiff
less
Define displacement
Movement from original position
Displacement is caused by
Application of a force
Force is measured in
Newtons
Equilibrium is
No net force
If force results in motion, the motion is opposed by
Friction
The displacement from equilibrium is labeled as a molecules…
Amplitude
Loudness is
Psychological perception of displacement, amplitude, intensity
Intensity is
Measurable and quantitative
The greater the displacement…
The louder the perceived sound
What is displacement measured in?
dB or decibles
T/F
Intensity is related how fast the molecules move
False
T/F
If you change frequency you have to change the intensity
False, frequency and intensity are independent of each other
Define frequency
How fast the molecules move
Does a faster frequency result in greater displacement?
No
Frequency is measured in
Hertz
Frequency is psychologically perceived as
Pitch
Perception of displacement is _____ while perception of frequency is ______
loudness, pitch
A faster vibration results in a faster…
Frequency
Phase is
Where the molecule is relative to equilibrium
What degrees can be equilibrium
0,180,360
What degrees can be maximum displacement
90,270
Vibratory motion is also called
oscillation
Oscillation is a back and forth movement through ____
equilibrium
What is the simplest type of vibratory motion?
Simple Harmonic Motion
define compression/ condensation
increase in density (molecules are closer together)
define rare fraction
decrease in density (molecules are farther apart)
define a longitudinal wave
the direction of the particle is parallel to wave movement & the wave moves in the same plane
eg: saloon doors burst open in the same direction that the force (push) was applied
eg 2: an example of non longitudinal wave would be a rock being dropped into a bond where the force is seen going in waves around the rock (ripples) instead of down (the same direction the force was applied)
