Given the Question and Answer pair, detect whether the answer is acceptable or not. Denote acceptable answer as "yes", otherwise denote as "no". An acceptable answer is consistent with the context in question, detailed, long, and uses general knowledge of English. Answers that are not definite and suggest a variety of options are not acceptable answers.

Question: This phrase is all over the internet. They will say that something is free as in 'free beer' and free as in 'free speech'. I have never really understood this. Are these the examples of two different types of 'free'? 
Answer: Wikipedia on Gratis versus Libre: Gratis versus libre is the distinction between two meanings of the English adjective "free"; namely, "for zero price" (gratis) and "with few or no restrictions" (libre). The ambiguity of "free" can cause issues where the distinction is important, as it often is in dealing with laws concerning the use of information, such as copyright and patents. And further: With the advent of the free software movement, license schemes were created to give developers more freedom in terms of code sharing, commonly called open source or free and open source software. As the English adjective free does not distinguish between "for zero price" and "liberty", the phrases "free as in free beer" (gratis, freeware) and "free as in free speech" (libre, free software) were adopted. [...] "Free software is a matter of liberty, not price. To understand the concept, you should think of free as in free speech, not as in free beer." Richard Stallman Emphasis added.
yes

Question: I understand the capitalization rule for nouns, proper nouns require a capital letter. Also, I should begin a new sentence with a capital letter. When & why "mom/dad" requires a capital letter ? (Reference- ELL- I am at Vapi where mom is hospitalised) mom: (n) informal term for a mother/North American term for mum. 
Answer: When it is their name, Mom and Dad would be capitalised: Dear Mom and Dad, I am just writing to let you know, that although everyone has a mom and a >dad, you are my special mom and dad. So, Mom, I just want to say 'brava!'; and Dad, 'bravo!'. I've just been telling Sis, that Mom's new coat is so cool. XX Here's the commentary from an exercise from BBC English on Line ...to have a roast chicken lunch with my mother. I can't wait! - mother does not need a capital 'M' as it is not being used to replace her name. If I said, "I am going to lunch with Mum", it would need a capital letter, but "I am going to lunch with my mum" does not.
yes

Question: is it 'a usual' or 'an usual'? 'A usual' sounds more correct in my head ('Today was a usual day.') than 'an usual', but u is a vowel. Which one is correct and why? 
Answer: Usual (pronounced /ju.u.l/ as in you) begins with a consonant sound and, as such, it should be preceded by a not an. As an aside, I cannot help but point out that the sentence Today was a usual day is not usually heard in regular conversation. Today was an unusual day is what one might hear, instead! Indeed, I rarely hear the construction a usual. The definite article is more commonly used, in my experience: That's the usual thing. In place of a usual, one would also be more likely to hear not an unusual: Today was a usual day / Today was not an unusual day This is a usual occurrence / This is not an unusal occurrence or This usually happens You are right in saying that a usual sounds weird. As speakers, we tend to avoid constructions which, though correct, do not flow easily from the mouth. In sum, the following are valid and commonly used alternatives: not [an] unusual the usual usually.

yes