Questions & Answers about Er braucht das Auto für Dienstag.
Why do we use für Dienstag instead of am Dienstag here?
am Dienstag tells us when an action happens (for example, he is driving on Tuesday). für Dienstag is used because Tuesday is the intended time span for the need—he needs it for that specific day. Just like in English, für marks the block of time the car is reserved for.
The lesson says für always takes the accusative case. Why isn't there an accusative article before Dienstag?
When using für with days of the week or months, German usually drops the article entirely. While für den Dienstag is grammatically correct (since days are masculine and den is the accusative article), it is much more natural to just say für Dienstag.
Is das Auto in the nominative or accusative case in this sentence?
It is in the accusative case because it is the direct object of the verb brauchen (the thing that is needed). Because Auto is a neuter noun, its accusative article (das) looks exactly the same as its nominative form.