鋼琴鍵盤，C4的基音頻率為 262 赫，C5的基音頻率為 524 赫。C4音和 C5音使用的弦線密度
相同，但是 C5弦長為 C4弦長的 60％，則 C5弦的張力是 C4的多少倍？
(A) 1.44 (B) 1.21 (C) 0.81 (D) 0.64
答案A
請附上詳細公式 謝謝
物理 音頻計算
2014-03-29 7:26 pm
回答 (5)
2014-03-29 8:41 pm
✔ 最佳答案
從 : http://www.school-for-champions.com/science/sound_from_string_equation.htm#.UzZKkqiSySo得到 : f = (1/2L)*√(T/μ)
wheref is the frequency in hertz (Hz) or cycles per second (頻率)T is the string tension in gm-cm/s² (張力)L is the length of the string in centimeters (cm) (絃長)μ is the linear density or mass per unit length of the string in gm/cm (線密度)√(T/μ) is the square root of T divided by μ in second
設 f4 = 262
f5 = 524
L5 = 0.6(L4)
T5 : T4 = ?
f4 = ((1/2L4)*√(T4/μ) (1)
f5 = ((1/2L5)*√(T5/μ) (2)
(2) ÷ (1) ==>
(524/262) = (L4/L5)(√(T5/T4)
(524/262)² = (1/0.6)²(T5/T4)
4 = (2.78)(T5/T4)
T5/T4 = 1.44
2014-04-28 8:12 am
2014-04-25 3:45 pm
2014-04-24 2:41 pm
2014-03-30 11:07 pm
收錄日期: 2021-04-27 20:33:49
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20140329000016KK02075