告別教育政策

friendlyguy

原帖由 hog.wash 於 10-11-16 00:02 發表


You said previously to Davidmimi " ...例如牛頓的萬有引力定理，只可應用於日常生活的物體大小，但去到如星體之超大物體或粒子之超細物體便不適用。 Einsten 的 廣義相對論 Theory of General Relativity 應用範圍比 ...

What do you mean by "size"? Are you referring to mass or volume? If you mean mass, I think it's matter since gravitation is proportional to mass.

I did not study physics or enginerring in U. However, from my limited knowledge in my A-level study, Newtonian mechanic is a special case of relativity and Quantum theory. When velocity approach to that of light or mass is very large, Einstein's theory must be use. However, if size is very small (sub-molecular level), Quantum theory comes into place. These create  lots of debate in the scientific world. That's why physical scientists is now working very hard for a "unified theory" to explain everything.

I also read from a book (sorry, I can't remember te title) that velocity and mass encountered during space travel nowaday is "small" and Newtonian mechanic can still be use!

I am not here to challenge anyone. I'm just want to know more and I'll be very happy if someone can teach me.

hog.wash

原帖由 friendlyguy 於 10-11-20 01:41 發表



What do you mean by "size"? Are you referring to mass or volume? If you mean mass, I think it's matter since gravitation is proportional to mass.

I did not study physics or enginerring in U. Howev ...

Dear Friendlyguy

對不起。原以為你是問Y2KChild，所以沒有回答。若有怠慢之處，罪過。

大小一詞先由Y2KChild使用，我想我們可理解成體積，而體積當與質量不同，否則我們無須有   質量 = 體 積 x 密度    的公式。但即使是質量，也只是兩物體之間引力的一個因素，其它因素重要的還有兩者問距離。

相對論的證明，其中一個例子是糾正水星運行軌跡用牛頓力學計算的偏差。水星是太陽系最小的行星。牛頓力學的偏差源於水星最接近太陽，兩者之間的引力比地球引力大得多，令牛頓力學失效。用牛頓力學計算太陽系其它行星軌跡並無大問題。

其實以上問題，稍為花時問google一下都有答案。

[ 本帖最後由 hog.wash 於 10-12-14 17:31 編輯 ]

cow

The interviewer ask, "What is pi?"
Mathematician says:
The ratio of circumference of a circle
                        to its diameter.

Computer Programmer says:  
3.141592653589 in double precision.

Physicist says:
3.14159 plus or minus 0.000005

Engineer says:
about 3.14.

Marketer says:
about 4.

Accountant says:
What do you want it to be ?

hog.wash

原帖由 MadonnaHK 於 10-12-24 13:46 發表

__________________________________

Uncle Edward,

昨日的我已死, 也不把昨日的我回到今日, 每日都是一個新的我, 請容下我昨天的失誤.

我們不曾對立過....

祝你和你的家人有一個愉快的平安夜...

你始終永遠是 ...

從不細理自己受儒、釋，道，基督教思想的影響孰大，但我信儒家的「慎獨」。不管他人知否，不管名號是甚麼，人總應該恪守自己信奉的道德標準。

我若口出惡言，傷害了我無心傷害的人，我自己就容自己不得。

但正如 inception 中所說的，一般情况下，在夢中死去，只不過是重歸現實而矣。

hog.wash

原帖由 MadonnaHK 於 10-12-27 13:43 發表


_____________________________

Hog.wash Sir,

可否就你所知的, 說說儒, 釋, 道, 及基督教,

你是基督徒嗎?

我說過我妻子不學無術，但她認識的 learned friends 倒是不少。其中一位黃先生，年青時在英曾與高錕先生是同事，後來在英某大學教書，退休後一個人回來住下。

幾個月他捧着一本厚厚的數學書上門，指着其中一條偏微分方程題目。問我怎樣解。原來老先生見舊同事患上腦衰退，怕起上來就拿出大學讀過的書重溫，讓頭腦做做腦操。我只好坦白：「大哥，我大學時最接近數學系就係試過同個數學系一年級嘅同房咋。」怎料黃先生說：「咁你太太又話你數學好。」「係就係，但佢講漏咗”小學”兩個字。」

你的要求，等於見隻馬餾打咗兩個跟斗，就叫佢整個七十二變嚟睇睇。唉，等我刨完蔡志忠嘅哲學系列至講吧。

annie40

Hi Eviepa,

I'm addicted to read 囝囝爸 and your inputs.  So informative, percetive and sometimes funny.  However, you really hurt my feeling when you decided to quit from this forum.  a bit like a good friend not call and turn up anymore.

Annie

edea

無謂又翻舊帳來算吧, "過街老鼠"一詞, 並不太禮貌.

近來馬君亦很自律, 我是很欣賞的, 希望馬君繼續keep it up, 我仍然相信, 不同意見, 不同立場, 仍然可以有精彩的討論, 不一定要人身攻擊對方來成就自己的.

edea