Conjugation of い adjectives - when do you conjugate them and difference between 新しい車 and 新車?


I'm studying Japanese at University (first year) and the only thing I can't
get my head around so far is い adjectives.

I understand how and what factors are needed to conjugate them, but do you
only conjugate い adjectives if they are at the end of the sentence working
like a verb or do you also have to conjugate them if they are before a noun?
I've been told different answers to this so it's a little confusing.

Also, in my Basic Kanji Book which we use to learn Kanji, two examples of ''a
new car'' are given in different places - 新しい車 (read as あたらしいくるま) and 新車 (read
as しんしゃ). Are there certain conditions needed to decide which one to use?

I know that I'm probably asking simple questions here and I'm probably just
being silly by not thinking about this in the right way but I've tried
understanding them by studying and searching online but I'm still confused so
I would be really grateful if someone could explain where I'm going wrong.




If an i-adjective is directly modifying a noun then it is written in the
dictionary form. No conjugation is necessary, so 新しい車 is correct. btw 車 is
pronounced くるま in this case.

新車{しんしゃ｝is a noun in its own right. It is not a combination of an adjective
modifying a noun.

Adjectives **can** be altered before modifying the noun. For example you can
say おいしそうなケーキ, a cake that looks delicous. In this case you are converting the
i-adjective into a na-adjective to modify cake, but that's a little more
advanced.

