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प्रश्न
Explain why does the rear mirror of a motorbike start Vibrating Violently, at some particular speed of motorbike?
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उत्तर
When the frequency of the engine of motorbike corresponds with the natural frequency of the rear view mirror, die resonance takes place. Thus, the rearview mirror vibrates with a larger amplitude violently.
संबंधित प्रश्न
Define the Resonance phenomenon?
The adjacent diagram shows three different modes of vibrations P, Q and R of the same string.

(i) Which vibration will produce a louder sound and why?
(ii) The sound of which string will have maximum shrillness?
(iii) State the ratio of wavelengths of P and R.
How does the medium affect the amplitude of free/natural vibrations of a body?
What are forced vibrations?
Why is a loud sound heard at resonance?
Why are the stringed instruments like guitar provided with a hollow sound box?
(i) Define resonant vibrations.
(ii) Which characteristic of sound, makes it possible to recognize a person by his voice without seeing him?
In Fig. A, B, C and D are four pendulums suspended from the same elastic string XY. The lengths of pendulum A and D are equal, while the length of pendulum B is shorter and of the pendulum C is longer. Pendulum A is set into vibrations.

- What is your observation about the vibrations of pendulum D?
- Give reason for your observation in part (a).
- What type of vibrations take place in pendulums Band C?
- Give reason for the answer in part (c).
