GMC Chevrolet Camaro 1998 Service Manual page 103

General Information
Amplitude
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2
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Centrifugal Force Due to an Imbalance
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90 180
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) Legend
(1) Location of Imbalance (Degrees)
Vibration Diagnosis and Correcti'on 0-91
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, we are
referring it to 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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