Kono kuruma wa atarashii/ atarashii desu.
This car is new.
Ano gaka wa yūmei da/yūmei desu.
That painter is famous.
When I-adjectives are used as predicates they behave as verbs. When atarashii is used as a predicate, it more specifically means "is new," rather than just simply "new." Therefore the copula da representing "is" does not get placed after it. (However, for the sake of politeness, desu can be placed after it). Alternatively, when na-adjectives are used as predicates they behave as nouns, When yūmeina is used as a predicate, for example, the stem-form (the form lacking na) must be followed by the copula da or desu.
Kono shigoto wa muzukashii.
This work is difficult.
Watashi-tachi no atarashii jimusho wa hiroi desu.
Our new office is large.
Ano yama wa kiken da.
That mountain is dangerous.
Chichi mo haha mo genki desu.
My father and mother are both healthy.
Hope this helps you understand Japanese more than before, and see you again!
°˖ ✧◝(○ ヮ ○)◜✧˖ ° こゆうきあいはら °˖ ✧◝(○ ヮ ○)◜✧˖ °