2021 dse 物理科 physics 綜合討論區

其實有咩問題啊？
做 conservation of mechanical energy不嬲都係睇頭尾相差架啦...
佢話neglect air resistance，咁未PE loss = KE gain

佢因為到尾都係講緊player serves the volleyball...
開波嗰下淨係given an initial speed咋嘛😂

加上佢都話
“Serves the volleyball by hitting the ball from rest at a height of 1 m”
換言之，個波一開始就係喺 h=1m

其實你係未搞錯咗18年同埋今年嗰條嘅設定😂
佢要俾steps分你緊係1M+1A

我估呢題最後加唔加pe都accept
太撚on9

人地條題目由頭到尾都係講開波🤷
乜你開波打個波嗰「刻」可以執完個波再開嘅咩？

睇落去係個情景唔sensible姐
但我覺得字面解䆁係interpret做1m開波

條題目... 一開波就同你講打個波
你哩啲其實就係不必要假設...

佢可能喺個場地角落頭執個波返去佢個位到開都有work done

一開始都冇嘢好討論

等marking啦
如果佢計PE嘅話我批個頭俾你煲湯又點話
我終於明點解啲Physics老師話學生成日自己加料，明明就唔關事🤷
The volleyball is served by the player. The player only hits the volleyball during the serving process. The the work done on the ball by the player equals the KE gain by the ball.
What’s the matter ?

Then the work done*

我會揀唔計GPE
因為題目第一句嘅語景係開波
serve the ball from rest

所以，我會覺得
(a) 問work done of serving the ball

人地俾咩情境你，你就計咩啦
講咁多狗屎垃圾就係因為你唔熟書

Physics 5** 90% cutoff而已
有10%慢慢跌😂

讀好啲mechanical energy哩課啦哥哥
狗屎垃圾係指你講嘅嘢，唔係話你啊

5**真係基本盤啦
你話HKAL Phy A，我就即刻甘拜下風喇

同埋考試唔洗你唸架喎
人地問乜，你就答乜，唔明有咩好唸

再加上，我又唔明你講一大抽嘢話你有幫人補習、又17 5**有咩意思，係想加強你論證嘅說服力？

放心，你講嘢有道理無論Phy U定5**，幫人補習定被人補習我都會認同架喎