Give examples of swinging movements. What is called mechanical vibration? What vibrations are called free vibrations?

1. Give examples of swinging movements. 2. What is called mechanical vibration? 3. What vibrations are called free vibrations? 4. What systems are called oscillatory? 5. What is called the vibration amplitude; period of fluctuations; vibration frequency? In what units are each of these quantities measured? 6. What is the mathematical relationship between the period and the frequency of oscillations? 7. How do the frequency and period of free oscillations depend on the length of the thread? 8. What vibrations are called natural? 9. What vibrations are called harmonic? 10. What is called a mathematical pendulum? Under what conditions will a real filamentous pendulum oscillate close to harmonic? 11. What value is called the phase of oscillation? 12. Give an example of oscillating bodies in the same phases, opposite phases. 13. What transformations of energy occur during vibrations? 14. What is called forced oscillation? 15. What phenomenon is called resonance? 16. Give examples of mechanical resonance. 17. In what cases can resonance be useful and in what cases harmful? 18. What are called waves? What are elastic waves? Give an example of waves that are not elastic waves. 19. What waves are called longitudinal; transverse? 20. Which waves – transverse or longitudinal – are shear waves; compression and tension waves? 21. Why transverse waves do not propagate in liquid and gaseous media? 22. What is called wavelength? What formulas can be used to calculate the wavelength and speed of wave propagation? 22. What is the source of the sound? What is called sound? 23. Mechanical vibrations, what frequencies are called sound and why? 24. What vibrations are called ultrasonic; infrasonic? 25. What is called a musical tone; noise? 26. What determines the sound volume? 27. What determines the pitch of the sound? 28. What is called an echo?

1. Mathematical pendulum, swing, cuckoo clock.
2. Mechanical vibrations – a movement in which the body periodically changes its position to the opposite, passing the equilibrium position.
3. Free vibrations – vibrations that, after excitation, occur without external influences.
4. Oscillatory systems – systems of bodies that can oscillate.
5. Amplitude of oscillations – the largest displacement of the body in modulus relative to the equilibrium position (m). The period of the oscillation is the time duration of one complete oscillation (s). Oscillation frequency is the number of oscillations per unit of time.
6.Frequency is the reciprocal of the period; period is the reciprocal of frequency.
7. The longer the thread, the less the vibration frequency, therefore, the time of one full vibration (period) increases.
8. Natural vibrations – vibrations performed without external influences on the body.
9. Harmonic vibrations – vibrations obeying the law of sine or cosine.
10. A mathematical pendulum is a small, heavy ball attached to a long, inextensible thread.
11. Oscillation phase – determines the displacement of the pendulum from the equilibrium position.
14. Forced vibrations – vibrations performed by the body under the influence of an external force that periodically changes.
15. Resonance is a phenomenon of a sharply increasing amplitude of forced vibrations when the frequency of vibrations of the driving force and the natural frequency of the vibrational system coincide.
16. Some people are capable of breaking crystal glasses with their voices. This is the most striking example.
17. An example of a useful resonance is the sounds of musical instruments, a harmful one is the destruction of buildings.
18. Waves – Disturbances spreading in space and moving away from the place of their origin. Elastic waves – propagating in elastic media. Electromagnetic waves are not elastic.
19. Longitudinal waves – oscillations in which occur along the propagation of waves., Transverse – oscillations in which propagate perpendicular to the propagation of waves.
20. Transverse – shear waves, longitudinal – compression.
21. Because there are no elastic forces in these media.
22. Wavelength – the distance between two points of the wave. oscillating in the same phases.