I'm quite puzzled as to why this answer I wrote got three downvotes (here).
The OP's question indicates they had a fundamental misunderstanding and probably got lost while self-studying the subject. Something which I can relate to as I self-study as well. So, due to that, I thought of writing the answer from scratch and explaining each concept with the best idea's I could get.
In comparison to mine, some of the almost dismissive answers were accepted over mine and it was this which led me to question the real purpose of the site. Does this site want answers with references and citations or just superficial answers with none of those?
From what I've heard people say, I understood this site as a knowledge repository/place where people could pool in knowledge to help a large group of people. Yet narrow and short answers are preferred over long ones that take time and effort to write.
Maybe my points and my answer is factually wrong... I don't know. I based my knowledge of my textbooks and made sure to say where exactly I got my ideas from so that my answer would be open for criticism.
The purpose of this post is to ask what exactly am I doing wrong... I perhaps guessed that it may have been that my answer was more tending to the teaching side than a direct answer side, but I felt op was so misguided that I had to go out and write it all.
Further, let's take the OP's question out of the picture. Even then, I do think that my answer would be useful for a large audience. I mean, wasn't this the reason that homework questions are shunned upon? (That they only help a narrow group of people.)
I recall once reading an established user of this website saying that the votes are a measure of how useful your questions and answers are for the site. I do not have the exact quote/citation. So, correct me if I am wrong, does this mean that people think my question is reducing the qualify of the site somehow?
One of the main reasons, I preferred this site over other q&a sites is that people were supposed to give trustworthy feedback and answers but I really am not feeling it on this one.
The actual question of the OP:
I felt some people are upvoting answers which is not even related to the OP's question. One person answered momentum conservation using the third law which was not even related to the OP's question...
I really can't understand why there is no decrease in momentum when kinetic energy is decreased in an inelastic collision.
This is the real question contained in the OP's subject and it is an exact quote which I took. They are simply asking how it is so in an inelastic collision that momentum is conserved, but kinetic energy is changed.
When I said useful to a wider audience, I meant this:
I wrote that as a point here because the OP had pinned up a few specific points out of the topic. I took those topics to the fundamentals and explained from the ground up. I was pretty certain that the OP was misguided as soon as I saw that they were asking about Noether's theorem for explaining the kinetic energy loss inelastic collision.
I did not mean that I think answers which are completely derailed from questions should be seen as valuable.
On the individual freedom's to vote:
True, I agree, but I imagine this site to be something more scientific rather than an opinion site. Sure, sometimes things are so complicated that we may have to bring in opinions here and there, but I think we should have the courtesy to explain what is wrong in a piece before giving it a negative reception.
When I got three downvotes I felt that maybe I am doing something very incorrect because it was the first time I got that many downvotes on an answer. I can not see it myself, but if someone else can see it then I'd be happy to listen if they were to point out legitimate criticism on the material that I have written.