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| Summary |
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- All vibrating and oscillating bodies are described by the length of time required for one complete cycle.
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- Time period (T) is the reciprocal of frequency (f).
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- Vibrations and oscillations are also characterised by terms like amplitude of vibrations which is actually the maximum distance the object spans, from its equilibrium point.
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- We have also seen that all vibrating/oscillating systems have a distinctive set of natural frequencies. A simple vibrating system has only one natural frequency (namely pendulum), whereas complex vibrating systems may have more than one natural frequency.
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- When a vibrating system is excited at its natural frequency, it “resonates” and its amplitude increases.
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- We have also learnt that waves are nothing but vibrations which move through a medium. Recollect that it is the wave (energy) that is moving through the medium, but not the medium itself.
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- When transverse waves are in motion through a medium, the particles of the medium vibrate perpendicular to the direction of propagation of energy.
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- When longitudinal waves are propagating through a medium, the particles of the medium vibrate parallel to the direction of propagation of the wave.
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- Another important aspect of the waves is that they do not go straight through openings or around barriers, but they spread out.
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- So, when waves move through a medium, no material is transported from one location to another. So, it is the disturbance that moves.
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- When two waves pass through the same region at the same instant of time, the individual disturbances add up together algebraically after which, each wave retains its own identity.
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