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प्रश्न
Explain why are soldiers asked to walk out of step while crossing bridges?
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उत्तर
When the soldiers walk in step, they produce some fixed frequency. If this frequency corresponds to the natural frequency of the bridge, the resonance can take place. This, in turn, will make the bridge to vibrate violently, and hence make it collapse. To avoid such a situation, the soldiers are asked not to march in step.
संबंधित प्रश्न
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.
Why is a loud sound heard at resonance?
In following figure shows A, B , C and D represent test tube each of height 20 cm which are filled with water up to heights of 12 cm, 14 cm, 16cm and 18cm respectively. If a vibrating tuning fork is placed over the mouth if test tube D, a loud sound is heard.
- Describe the observations with the tubes A, B and C when the vibrating tuning fork is placed over the mouth of these tubes.
- Give the reason for your observation in each case.
- State the principle illustrated by the above experiment.
Why are the stringed instruments like guitar provided with a hollow sound box?
The diagram below shows three different modes of vibration P, Q and R of the same string of a given length.
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 |
 |
| P | Q | R |
- Which vibration will produce a louder sound and why?
- Which vibration will produce sound of maximum shrillness (or pitch) and why?
- What is the ratio of wavelength of vibrations P and R?
The rearview mirror of a motorbike starts vibrating violently at some particular speed of the motorbike, what could be done to stop the violent vibrations.
Explain a person walking past a railway line, in the middle of night hears a ringing sound along with the sound of his footsteps.
