what are forced, damped and free oscillations and could u please compare any two musical instrument.?

Question

please compare the instruments on the basis of the quality, pitch and loudness of the sound produced by them.

Answer 1

Free oscillation is when a system oscillates freely without friction and loss of energy, hence it goes on forever.

Forced oscillation is when an external force acts on the system, causing it to oscillate. If the frequency of the external force is the same as the natural frequency of the system, resonance occurs and the system oscillates with an infinite amplitude. That is why glass breaks when a soprano singer sings at a high pitch as the frequency of the sound is the same as the frequency of the glass (with is very high).

Yes you can. You can compare the waves of the sound produced and it tells everything.

Answer 2

A piano (and guitar) can demonstrate the modes of vibration. If you hold the sustain pedal down and strike a key the hammer will strike the piano string and back off initiating forced oscillations. Other piano strings (especially octave strings) will spontaneously vibrate in free oscillation due to resonance. When you release the sustain pedal all the string oscillations will be damped.

The guitar can perform the same way with forced oscillations when a string is plucked and other open strings (especially octaves) may resonate in free oscillation. The fingers of either hand can damp a string by touching it.

Both pianos and guitars have provisions for amplifying the oscillations. Pianos use double and even triple strings to increase the sound energy of the higher notes and a soundboard (or bellly) to increase resonation. Guitars may use double strings (twelve string vs six string) to increase volumn and acoustic guitars are hollow with a sounding hole to increase resonance. The quality of the sound of a guitar can be varied by where the string is plucked. If plucked in the middle, only the fundamental (lowest tone) is produced. The piano hammers strike strings at one end which initiates the fundamental and a rich collection of overtones because the vibrations are far more complex with the string dividing up into fractions of its length. Guitars can be plucked at one end to achieve the same effect. Hope that helps a little.