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Answer» (1) Free vibrations and resonance: | Free vibrations | Resonance | | 1. These are produced when a body is distributed from its equilibrium position and released. | 1. It is produced by forced vibrations when the external periodic force has the frequency equal to the natural frequency (or nearly so) of the body. | | 2. The energy of the body remains constant in the absence of dissipative forces. | 2. Energy is supplied continuously by the external periodic force to compensate the loss of energy due to the dissi‐ pative forces. |
(2) Forced vibrations and resonance : | Forced vibrations | Resonance | | 1. These are produced by an external periodic force of any frequency | 1. It is produced by an external periodic force whose frequency is equal to the natural frequency (or nearly so) of the body. | | 2. The frequency of vibrations is, in general, different from the natural frequency of the body | 2. The frequency of vibrations is the same (or nearly so) as the natural frequency of the body. | | 3. The amplitude of vibrations is usually very small. | 3. The amplitude of vibrations is large. | | 4. Vibrations stop as soon as the external force is removed. | 4. Vibrations continue for rela‐ tively longer time after the external force is removed. |
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