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प्रश्न
Give two examples of forced vibrations.
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उत्तर
(i) The vibrations produced in the board of a guitar when its string is made to vibrate.
(ii) The vibrations produced in the tabletop when the stem of a vibrating tuning fork is pressed against it.
संबंधित प्रश्न
What are mechanical waves?
When a troop crosses a suspension bridge, the soldiers are asked to break steps. Explain the reason.
Why are the stringed instruments like guitar provided with a hollow sound box?
Two pendulums C and D are suspended from a wire as shown in the figure give below. Pendulum C is made to oscullate by displaying it from its mean position. It is seen that D also starts oscillating.

(i) Name the type of oscillation, C will execute.
(ii) Name the type of oscillation, D will execute.
(iii) If the length of D is made equal to C then what difference will you notice in the oscillations of D ?
(iv) What is the name of the phenomenon when the length of D is made equal to C ?
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).
A bucket kept under a running tap is getting filled with water. A person sitting at a distance is able to get an idea when the bucket is about to be filled.
(i) What change takes place in the sound to give this idea?
(ii) What causes the change in the sound?
Explain Why are stringed musical instruments provided with large sound boxes?
What do you understand by forced vibrations?
What do you understand by free vibrations of a body? Draw a displacement-time graph to represent them. Given one example.
