一個波的波函數可以用 y(x,t) = 0.03sin(5πx + 4πt) 來表示，其中 x 和 y 的單位為公尺，而 t 的單位為秒，若往右為 +x 的
方向，則此波的速度為？
(A) 0.80 m/s 向左 (B) 1.25 m/s 向左 (C) 0.80 m/s 向右 (D) 1.25 m/s 向右。
ANS: A
請詳解
物理 波速
2010-05-20 1:53 am
回答 (4)
2010-05-20 6:54 am
✔ 最佳答案
y(x,t) = 0.03sin(5πx + 4πt)過一週期後 y1(x1,t1) = y2(x2,t2)
=> 5πx1 + 4πt1 = 5πx2 + 4πt2
=> -5( x2 - x1 ) = 4π( t2 - t1 )
等號兩邊消去 => -5( x2 - x1 ) = 4( t2 - t1 )
{ 註: 因為過一週期 => t2 - t1 = 週期(T) => x2 - x1 = 波長(λ) }
=> -5λ = 4T
等號兩邊同除T => -5λ/T = 4
{ 註: v=f*λ=λ/T}
=> -5v = 4
so, v = - 0.08 m/s = 0.08 (向左)m/s
故選A
參考: 我
2010-05-20 7:46 pm
y(x,t) = 0.03sin(5πx + 4πt)
wave number, k = 5π
Angular frequency, w = 4π
Speed, v = w/k = 4π/5π = 0.80 m/s
The answer is A.
wave number, k = 5π
Angular frequency, w = 4π
Speed, v = w/k = 4π/5π = 0.80 m/s
The answer is A.
2010-05-20 5:08 am
y=Asin(kx+wt)
w>0-->往左
w<0-->往右
w>0-->往左
w<0-->往右
2010-05-20 3:35 am
TO Prof. Physics
Why the vector is negtive ? How to expect ?
Thank you!
2010-05-27 12:21:13 補充：
阿賢好像多打了一個0
Why the vector is negtive ? How to expect ?
Thank you!
2010-05-27 12:21:13 補充：
阿賢好像多打了一個0
收錄日期: 2021-04-19 22:15:46
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20100519000010KK05280