Not unless it is part of a proper noun (a named thing or group) such as Capital Police. Referring to cities, a capital is the seat of government. The name (e.g. Ottawa, New Delhi) is capitalized, but not the word capital when it refers to it.
Yes, when the word "capital" is used in reference to the capital city or financial assets, it should be capitalized. However, when it is used in a general sense, like "capital punishment," it should not be capitalized.
Yes, it is used capitalized.
No it shouldn't be capitalized.
Yes. In fact it should always be capitalized.
The letter Pi (π) is capitalized to Π
A proper noun has its first letter capitalized.
No, it shouldn't be capitalized.
Fahrenheit is a proper noun and should be capitalized.
It's a rule that the pronoun, I is always capitalized simply because I is how you would address yourself. If yourname gets capitalized always so does the pronoun, I."A" can be capitalized too but only at the beginning of the sentence. It is an article. It doesn't represent a person'sname.
Yes, "The Capital" should be capitalized because it is a proper noun and the word "capital" is an essential part of its title.
Yes, "Arabs" should be capitalized when referring to the ethnic group or people from the Arab world.
No, past does not have to start with a capital letter.