Tradução de "you guys gonna rock"

The word GUY is an informal word and means "cara", "rapaz" or it can be translated as "pessoal".
For example:

*He is a nice guy. - Ele é um cara legal.
*Hello guys! - Olá, pessoal!

The word ROCK, as a verb, means "balançar", "agitar".
For example:

*He rocked the baby to sleep. - Ele balançou o bebê para dormir.

So, the sentece "you guys gonna rock" can be translated as : "Pessoal, vocês vão balançar!" or "Vocês vão agitar"

I think it helps you.

Obrigado pelas explicações, ajudaram muito.

Tinha visto na web algo como, "Vocês são fortes" e "Vocês tem a força".

Could be. And it could mean "vocês vão arrasar!"

You rocks/you guys rock! is a known expression that means, you are great! (generally said in awe when somebody helps you to solve something very tricky. and sometimes making it seeming as it´s too easy!)

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In a more literal way, it could have to do "dance" (or sing, or enjoy it) for example, mainly in Rock In Rio. he hee.