[2022] DSE 物理科Physics討論區

LQ 3b
Newtons lawS of motion
姐係要1+3 or 2+3

係 我用1+3 但2分 好chur

Q11點prove

1分姐
我用2+3
想知點用1解 學下野

如果frictionless 個答案就唔同
但有friction 直接M+ m
好似係

11?
same speed because of same loss of PE
time different becasue different path

The force exerted on the drone by air is equal to the weight of the drone. There is no net force exerted on the drone. According to the Newton’s first law, if there is no net force exerted on the drone, it would keep at rest and afloat. (Due to its inertia)

Yes, mainly heat loss by conduction

睇錯咗佢speed係問張圖入面嗰個moment嘅speed，圈錯咗D

就係諗緊different path/distance係咪一定唔可以same time
先快後慢vs先慢後快
諗唔到點樣qualitatively prove

Yes, because 直線 is shortest path

先a大d果個會有著數行快d

Sry 睇錯野 可以無視

樓上兩個討論緊最速降線
但題目係
先速度較慢，再較快

我都諗緊有無可能兩條path time一樣
數學上睇有可能，但証明有點難

可以一樣 因為直線唔係最快
其中一段路似擺線 個度就可以追返啲時間
不過in general唔同path唔同時間

好明顯係b，當m+M係一個object

唔用數學真係諗唔到點argue 時間唔一樣

睇哂paper 1同2，mc比上年淺少少，1b就差唔多，cutoff應該比上年高1-2%

Q14 Why not D?

Q14 hai Mai do wrong? Shd be D wo I think