does anyone know a good website or source to learn physics in Japanese?

what does this mean: うちにわ　には　にわ、にわ　には　にわ、　にわとりが　います

is this correct? みなさん、今日は。日本語がもっと上手になるためにりゅう学生をなることにしますからだけ韓国に出て、にほんにくるだそうとおもう。 Hello everyone. In order to become more good at Japanese, I decided to become an exchange student, I think that it seems like only yesterday that I left Korea and came to Japan..... Does the eng translation even make sense?? T.T

what is the best way to translate?

what does 無料 mean?

Does anyone know a good website to revise Japanese for exams?

Does anyone know a good website where I can learn from untranslated Manga/comic?

I am a bit confused about the translation of せかいの中の日本、japan in the world, if particle　の is equivalent to ~'s.