2021 dse 物理科 physics 綜合討論區

冇錯 最簡單 有心睇2-3個鐘已經可以由零學哂
係比較多野背 但數易計concept易明
唔知點解冇咩人揀又冇咩學校有教
當然如果真係對Physics有興趣可能讀E1E2比較好

Yes

唔鐘意Phy，第時做唔到醫生又想睇下啲醫生做乜
E4就幾好

Btw concept易唔易明都係睇下老師點講解嘅啫😂

Btw 5aiii 係咁解咩

咁你點解釋？開放討論

有小小位錯喎
Q2bii 你冇寫到volume remains unchanged 同埋less violently
Q2cii你冇用hence (pressure drop)，有小小危...

Q3c 佢個angle太低可以會俾個網截住咗...
Q3d t increases then F decreases

Q4aiii mg = (M+m)a
Q4b carrying effect, M =

Q5aiii m decreases simultaneously, 睇下佢點俾，上次佢marking係俾m decreases

Q6biii real image 用實線畫、你mark咗F做L但F又冇mark

Q7ai the metal sheet is moving to the left
Q7aii electrical energy would finally convert to thermal energy

我估大約70分，都有*

我答 rate of change of momentum decrease, thrust decrease, thus a decreases

The rocket keeps expelling the gas in the same rate

3b(i) 點解係descending?

change of momentum will increase
因為架火箭accelerating緊
你去youtube睇下crew dragon嘅發射直播
都見到火箭會愈黎愈快架嘛 acceleration都會升

point B 過咗mid point

唔明 但d都係take 9

67 paper 1 B 應該78到

因為你A同C唔係對稱，C個位係低啲

如果我要喺右邊場搵一個位係同A對稱，就要喺C前面，let say point X.

A同X中間先會係flying horizontally—> 但係 B喺A同X中間點嘅右邊，所以係descending

咁樣明唔明？

78都唔錯喎

明了

夠5**

有冇興趣做埋paper2, 想更加firm 個 answer

你想要邊個Elective？E1 E2 我做起咗

2,3 唔該師兄

姐係佢最高個點 應該係喺個網前少少

想問E3最尾嗰條邊個regenrative system mode has the highest effectiveness🙇