B.Crowell - Vibrations and Waves, Vol
.3.pdfGlossary
Amplitude. The amount of vibration, often measured from the center to one side; may have different units depending on the nature of the vibration.
Damping. the dissipation of a vibration’s energy into heat energy, or the frictional force that causes the loss of energy
Driving force. An external force that pumps energy into a vibrating system.
Frequency. The number of cycles per second, the inverse of the period (q.v.).
Period. The time required for one cycle of a periodic motion (q.v.).
Periodic motion. Motion that repeats itself over and over.
Resonance. The tendency of a vibrating system to respond most strongly to a driving force whose frequency is close to its own natural frequency of vibration.
Simple harmonic motion. Motion whose x-t graph is a sine wave.
Steady state. The behavior of a vibrating system after it has had plenty of time to settle into a steady response to a driving force. In the steady state, the same amount of energy is pumped into the system during each cycle as is lost to damping during the same period.
Quality factor. The number of oscillations required for a system’s energy to fall off by a factor of 535 due to damping.
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Index
A
absorption of waves 65 amplitude
defined 14 peak-to-peak 14
C
comet 11
D
damping defined 24
decibel scale 23 Doppler effect 54 driving force 26
E
eardrum 26 Einstein, Albert 12 exponential decay
defined 24
F
Fourier’s theorem 73 frequency
defined 12
G
Galileo 16
H
Halley's Comet 11 harmonics 74 Hooke’s law 15
I
interference effects 70
M
motion periodic 12
O
overtones 74
P
period defined 12
of simple harmonic motion. See simple harmonic motion: period of
periodic motion. See motion: periodic pitch 11
principle of superposition 40 pulse
defined 40
Q
quality factor defined 25
R
reflection of waves
defined 62 reflection of waves 62 resonance
defined 28
S
simple harmonic motion defined 15
period of 15 standing wave 75
steady-state behavior 26 swing 26
T
timbre 74 tuning fork 14
W
work
done by a varying force 12, 14, 16
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Photo Credits
All photographs are by Benjamin Crowell, except as noted below or in captions. Photos from PSSC Physics are used under a blanket permission appearing on the copyright page of PSSC College Physics.
Chapter 2
Tacoma Narrows Bridge: Still photos and a movie of the bridge’s collapse were taken by an unknown photographer.
Nimitz Freeway: Unknown photographer, courtesy of the UC Berkeley Earth Sciences and Map Library. Brain: R. Malladi, LBNL.
Chapter 3
Painting of ocean waves: Hokusai
M100: Hubble Space Telescope.
Chapter 4
Human Cross-Section: Courtesy of the Visible Human Project, National Library of Medicine, US NIH.
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