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Lecture 8. VibrationsSmall deviations from equilibrium
Harmonic oscillation is the periodic variation of a quantity, which can be expressed as a sine or cosine function. The following classifications are used. On the basis of proceeding from the nature of oscillations: mechanical and electromagnetic. On the basis of proceeding from external forces: free and forced oscillation. On the basis of proceeding of the energy changing: undamped and damped oscillations. On the basis of proceeding from the form of equations: harmonic and unharmonic oscillations. Characteristics of harmonic oscillations: - the period T is the time of one full oscillation; - the frequency n is the number of oscillations per unit of time:
Any harmonic oscillation can be illustrated by the graph or by the vector diagram. Fig.8.1 represents graph of function
Figure 8.1
For vector diagrams complex numbers are used. Any complex number contains
The vector is of 2 m length and is situated under the initial angle Figure 8.2
Date: 2015-01-12; view: 1287
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