Question

1) explain why musical instruments like guitar are provided with hollow box.
2)when a vehicle driven at high speed , sometimes rattling sound is heard. explain why.

Answer 1

Musical instruments are provided with a hollow box. eg- guitar. In the musical instruments ,if the string is set into vibration ,the forced vibrations are produced in the air inside the box. Since area of the hollow box is large ,so it sets a large volume of air into vibration of the same frequency as that of string. Therefore, a loud sound is produced due to resonance. The sound produced by vibrating string is too weak to be heard. Rattling sound of vehicles is due to resonance That is,At certain speed the frequency of engine becomes the same frequency of the body It begins to vibrate vigorously and hence rattling sound is heard