Physics 312 Lecture: "Superposition of Waves and Standing Waves II."
Apr 13, 1998
- Standing waves in a tube open at both ends are constrained
to have specific wavelengths and frequencies
- Standing waves in a tube open at only ONE end are constrained
to have slightly different specific wavelengths and frequencies
- Resonance occurs when some periodic force drives a system
with a frequency close to the natural frequency of the system
- If two waves with ALMOST, but not quite, the same frequency
interfere, the result is a wave with a time-varying amplitude;
we call the slow variations in amplitude "beats"
- The beat frequency is simply the difference between the frequencies
of the two original waves
- Complex waves are combinations of a fundamental frequency and
some of its higher harmonics
- The different shapes of complex waves produced by different
musical instruments are detected by our ears as
different timbres
- Any complex wave can be expressed as the sum of simple
sine and cosine waves; this is called Fourier analysis
This lecture discusses material in Chapter 18 of Serway.
