2021 dse 物理科 physics 綜合討論區

君夫人陽貨欲

522 回覆

6 Like 5 Dislike

你的備用電郵 2021-05-07 00:05:04

比錢買啦Ching goodnotes幾好

愛因_絲打 2021-05-07 00:09:02

用ipad內置

天水圍電車男 2021-05-07 00:14:45

ic 見到了

thanks

ヒストリア 2021-05-07 03:01:39

讀囇1234 考嗰陣揀最順手嗰兩個

尚恩曼德斯 2021-05-07 07:40:34

通常最後兩個都會成為marking
當然最完備係分埋case

陝西省顯微鏡 2021-05-07 07:44:49

個PE係邊個俾重要？我答唔答你同你做唔做到係冇衝突...

考試就當然係做人地要你做嘅嘢... 人地條題目個重點好明確，serves the ball by hitting the ball，個volleyball player喺條題目係做緊hit the ball哩一個動作...

如果照你咁講，佢事前發生嘅嘢係要計埋入去，你要計嘅work done係沒完沒了。

另外，我就唔知你點解會覺得我係話你piece of shit，我一直都係講緊你講嗰啲嘢係狗屎垃圾，即係廢話咁解。
跟住批頭嗰句，我又唔明喇，啲補習老師都係會話：「今年唔出我批個頭落嚟俾你。」咁佢地又係起晒鋼？

陝西省顯微鏡 2021-05-07 07:52:54

Btw 個PE係邊個俾？我都唔知

個情況好簡單，你讀力學會唔會唸下「力」究竟係啲乜嘢嚟？

陝西省顯微鏡 2021-05-07 10:25:09

會注意

淫賤老闆肖秘書 2021-05-07 16:45:12

B field由N to S，左邊個Eddy係想maintain，右邊個eddy想resist，咁向右先啱呀嘛？

香港高考生 2021-05-07 16:48:05

should be left, eddy current induced at the left should be clockwise by right hand rule

淫賤老闆肖秘書 2021-05-07 16:52:15

Clockwise => induced B field pointing downwards
anti-clockwise => induced B field pointing upwards
我睇過兩三次我真係右手睇喎
唔係咩

愛因_絲打 2021-05-07 16:55:05

向左
left side leaving field (decay in B field) -> clockwise current to produce B field of same direction (reinforce)
right side entering field (growth in B field) -> anticlockwise current to produce B field of opposite direction (cancel each other)

淫賤老闆肖秘書 2021-05-07 16:57:07

Assume that the magnet was going left, taking downward as +ve, the B field would be stronger at left and weaker at right. By Lenz’s law, the eddy current on the left should produce -ve B field (pointing upward) and that on the right should do the opposite. By right hand grip rule, to produce B field pointing upward, eddy current should be anti-clockwise.
Contradiction arises.
真係錯