I've answered in English, since it's my native language, but I'll attempt a translation to French! :|
"She is dead" is the simple present tense. "morte" in this case, is an adjective
Subject - verb - adjective
She is dead
Elle est morte
"She died" is simple past tense. However, Google has used Past Perfect tense to translate1. In this case, "morte" is the past participle.
Subject - simple past
She died
Elle mourut
Google has used:
Subject - auxiliary verb - past participle
Elle est morte
She has died (English uses "to have" as the auxiliary)
comment je peux les distinguer ..
Sometimes language is ambiguous, ask another question to clarify :)
Please feel free to correct any mistakes!
"She is dead" est le présent de l'indicatif. En ce cas, "morte" est un adjectif.
Sujet - verbe - adjectif
She is dead
Elle est morte
"She died" est le passé simple, mais Google a utilisé le passé composé dans sa traduction. Dans cet exemple, "morte" est le participe passé.
sujet - passé simple
She died
Elle mourut
Google a utilisé:
Sujet - verbe auxiliaire - participe passé
Elle est morte
She has died (L'anglais utilise l'auxiliaire "avoir")
comment je peux les distinguer ..
Quelquefois des langues sont ambigües, tu peux poser une autre question. ;)
1. This site claims is is the most common, so it seems reasonable as a default