Wave motion

2014-08-03 5:31 am

有樣野好唔明。即係我頭先睇到particle vibration period 的定義係up down up 先叫一個complete revolution
但係點解wave motion period 係成兩個crest +1.5個troughs先叫1個complete revolution 呀？

更新1:

http://postimg.org/image/m3644jv3j/ http://postimg.org/image/8jdpd1znt/ 以上係我覺得又幾相似但晤明的definition.

更新2:

一d都吾明。

回答 (1)

天同

2014-08-03 7:08 am

✔ 最佳答案

In fig 5.2f, at t = 0, the vibrator is moving downward, and it produces a complete trough after returning to the equilibrium position at t= 0.25 s. At this time, the vibrator is moving upward. It produces a complete crest after returning to the equilibrium position at t = 0.5 s.

Thus, the vibrator performs a complete vibration in 0.5 s and which produces a complete wavelength (i.e. one trough plus one crest). Hence, the period of the wave is 0.5 s.

The path taken by the vibrator is that shown in fig.5.2c, the first blue vibration from the left (i.e. the one next to the red vibration).

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