Chapter 2- Wave Relationships
(many thanks to the HyperPhysics website)

Simple Harmonic Motion
A body will undergo SIMPLE HARMONIC MOTION when the force that tares to restore the object to its rest position is proportional to the displacement of the object. A pendulum and a mass on a spring both undergo this type of motion which can be described by a SINE WAVE
As you watch an object at the end of a swinging pendulum or an object on the end of an oscillating spring, you can 'see' the

Conservation of Energy Principle

in action. In either case, when the object changes direction it momentarily 'stops' and the total energy resides in

Potential Energy

As the object speeds up in it's swing or oscillation there is a point at which it is moving as fast as it will move, at this point the total energy resides in

Kinetic Energy

Total Energy   =   Potential Energy   +   Kinetic Energy

    In sound applications, a resonant frequency is a natural frequency of vibration determined by the physical parameters of the vibrating object. This same basic idea of physically determined natural frequencies applies throughout physics in mechanics, electricity and magnetism, and even throughout the realm of modern physics.
Click to see a video of the destruction of this bridge by a small but steady wind.

Questions from Chapter 2

1) Explain Resonance Frequency using two examples.



2) What are the ranges of frequencies for cats, dogs and humans?

3) What are the different categories of waves---explain?


4) What are the Harmonics of Open Air Column?



5) How can one demonstrate harmonics using a slinky?

Unit Analysis Practice
Work them out first!
Unit Conversions

1) How many miles in a light year? That is, how far does light travel in a year?
(speed of light = 186,000 miles/sec)

(Thursday night)



2) How many grams of water are there in a cubic meter container?
(Density of Water = 1 gram/cubic centimeter)

(Thursday night)

3) You receive a ton of gold. How much money does this represent at $312 per ounce?
How large is this chunk of gold in cubic centimeters?
(Density of Gold = 19.6 grams/ cubic centimeter)

(Thursday night)

Knowing Fourier Analysis will make you smart and valuable

Fourier Analysis is simply the decomposition of any complicated-looking signal into its sine and cosine wave components.
It's amazing that we are actually able to re-create this signal from basic sine waves!

Sound Spectrograph

    The Sound spectrograph produces a "print" which shows fundamental frequency, harmonics and intensity of the voice. This is used to identify subtle, but crucial changes in voice quality that can then be treated. The spectrogram identifies the presence of noise in the voice, such as tremor, pitch breaks and abrupt starts.

An excellent primer on speech synthesis:  
Speech Synthesis

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