As a Turkish native speaker, i do not understand what "uzun" means here.
it means the book has a lot of pages, it is actually a very typical expression in Turkish. It could of course also mean that the book literally has a long size
I beg to differ. I think "Bu roman/Bu öykü uzun mu?" is more common and appropriate in Turkish. I never say "Bu kitap uzun". It could be "Bu kitap hacimli." or "Bu kitap (çok) kalın."
is hacimli means that the book is with big sizes?
It would mean that it is large in size (like it is bulky)
Cevabı: Evet! Bu kitap bitmiyor!
i have been asked a similar question somewhere else, please can someone clarify why it is not "bu kitabi uzun mu". thank you
Book is subject in the sentence. You can use the accusative only for direct definite objects, but never for subjects.
I think this implies that the book is physically long in dimensions. One can say that the story/script/play etc is long, but would say that the book is thick or bulky (unless, of course, it is dimensionally a long book!)
Why is "Is this a long book?" wrong?
Because that would be "Bu uzun bir kitap mı?".
Please feel free to correct me here: I'm not a native speaker of Turkish.