Yes. They all vibrate, even just the slightest bit.
A chordophone is any musical instrument that makes sound when the strings vibrate or if the strings are stretched between two points. Examples are the violin and the guitar, so no, they are not percussion instruments.
Many instruments belong to the percussion family. For example, drums of all sorts are members of the percussion family. Also, rattles are considered percussion instruments.
A Drum or Drums, are part of the Percussion family :)
All drums are percussion instruments.
Most percussion and string instruments operate of vibrations to produce sound. Drum heads, xylophone bars, strings and reeds all vibrate on instruments that use them to produce sound.
aerophone
All can be considered as a percussion instrument but the Chordophone is not really a "Main" category in percussion. The two major category in percussion are Membranophones and Idiophones but there are chordophones that can be considered as a percussion instrument. An example of this is the piano. It produces sounds by its strings so its a chordophone but the strings are hit by little hammer so that they would vibrate and produce sound.
Percussion instruments are instruments such as the drums. The guitar can be used for percussion although it is a string instrument. No, percussion instruments are not used for playing the melody.
Percussion instruments are instruments that can be tuned or not but tuned instruments are tuned.
timpani
There are a lot of Percussion instruments used in an orchestra but here are some of the common ones:PianoTimpaniXylophonesCymbalsTrianglesSnare drumBass drumTambourineMaracasGongChimesCastanetsCelesta, And etc.
They are classed as percussion instruments.