ChuN.3.

引用:

原帖由 kiwakwok 於 2010-10-30 11:26 AM 發表
I think your teaching has made a mistake:

The following equation are used to describe the transverse velocity of a standing wave:
29704

However, for the traveling velocity, you can still use th ...

文憑試程度 無教過第1條方程
咁如果要描述駐波速率 用第2條方程 系米錯??

kiwakwok

Both equations are correct, but they are describing different things.
You teaching mixed up these two things, that's why he gave you a wrong answer initially.
In your case, use the second one is definitely correct.

1) Transverse velocity
This concept is in the topic of simple harmonic motion and which is out of the scope of the DSE Physics.

2) Traveling velocity
This is what you know and what you should know.

aayapoch

Velocity 係constant 係因為佢係睇個medium only (e.g. air, water, vaccum)
而由v=frequency x wave length 得知 wave length 係會因frequency change 而 change (velocity 係constant 同一條string)
但係why velocity 會增加? 咁係因為當個wave 反彈左之後會form 左interference 當2個in phase 既wave 走埋一體既時候會form 左antinode 而係e個時侯佢個Kinetic energy 係最大..由KE=不得1/2mv^2 e 係equation 可見..velocity 係增大左!

ChuN.3.

引用:

原帖由 aayapoch 於 2010-11-4 06:36 PM 發表
Velocity 係constant 係因為佢係睇個medium only (e.g. air, water, vaccum)
而由v=frequency x wave length 得知 wave length 係會因frequency change 而 change (velocity 係constant 同一條string)
但係why vel ...

但系牙sir已經承認左佢錯

aayapoch

個velocity change 只係intantenus