Please help answer questions 13 and 14 a)b)

comes from the piano. Explain this phenomenon. Why might more than one piano string respond? 13. A steel guitar player produces a first overtone by plucking the string at the one-quarter point while gently holding the side of his finger at the midpoint of the string. Explain why this works. Where should the string be plucked and touched to produce the second and third overtones? (This can be demonstrated on the laboratory sonometer, or on any other stringed instrument such as the guitar or violin.) 14. Try the following on a piano. (a) Slowly depress middle C without sounding the note. (This raises the damper from the string and allows it to vibrate freely.) Strike the Cs below middle C one at a time and listen for any sound produced by middle C. (b) With middle C still free to vibrate, sound the following notes: C sharp below middle C, G above middle C, high C, C 5/m/MzYyNTAwMTgzODYy/details above high C. Explain your observations using your knowledge of reso- nance and overtones. 15. The voice of a person who has inhaled helium is high pitched and sounds funny. Why? 16. When you whistle through your lips how do you control the pitch of the whistle