GMC chervolet camaro 1999 Service Manual page 83

0-80 Vibration Diagnosis and Correction
Amplitude
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Centrifugal Force Due to an Imbalance
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(1) Location of Imbalance (Degrees)
General Information
Legend
(1) Maximum
(2) Minimum
(3) Zero-to-Peak Amplitude
(4) Peak-to-Peak Amplitude
Amplitude is the maximum value of a periodically
varying quantity. Used in vibration diagnostics,
amplitude is the magnitude of the disturbance. A
severe disturbance would have a high amplitude; a
minor disturbance would have a low amplitude.
Amplitude is measured by the amount of actual
movement, or the displacement. For example, consider .
the vibration caused by an out-of-balance wheel at
80 km/h (50 mph) as opposed to 40 km/h (25 mph). As
the speed increases, the amplitude increases.
Free Vibration
Free vibration is the continued vibration in the absence
of any outside force. In the yardstick example, the
yardstick continued to vibrate even after the end was
released.
Forced Vibration
Forced vibration is when an object is vibrating
continuously as a result of an outside force.
270 360
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(2) Centrifugal Force Acting on Spindle
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