Why is 燃える + ゴミ = burnable? But the verb is not in ta-form

Question

I saw this in the book.

管理人{かんりにん}: 燃{も}える ごみは 月{げつ}・水{すい}・金{きん}の 朝{あさ} 出{だ}して ください。

I remember that If we want to use a verb as an adjective, we need to change a verb into the Ta-form, but this one is the verb in a dictionary form. Why is that?

Answer 1

I think you shouldn't think about the past tense of the verb here, because it has a completely different meaning.

燃えたゴミ

Literally means "garbage that burned" (= burned garbage). So it cannot be used as a potential form to mean "burnable".

燃えるゴミ

Is the correct form to use. It literally means "garbage that burns" so it could be translated by "burnable".

Also, you should forget the idea that a past-tense verb is an adjective, its translation might look like it's an adjective, but it's still a verb and it should be seen as such, even though we translate it by an adjective to make the translation sound more natural.