Learn Hardcore German: Im Kurs ist die Mehrheitsmeinung, dass diese Übung schwer ist. - In the course the majority opinion is that this exercise is difficult.

in + dem Kurs → im Kurs
This contraction is very common and completely neutral in standard German.
It works the same way as:
- an dem → am
- bei dem → beim
- zu dem → zum

You can say in dem Kurs, and it’s grammatically correct, but it usually sounds a bit heavier or more emphatic. In most everyday contexts, Germans will prefer im Kurs.

What case is im Kurs, and why?

Im Kurs is dative.

The preposition in can take either accusative or dative:
- Accusative = movement into something (direction)
  - in den Kurs gehen – to go into the course / to join the course
- Dative = position in something (location)
  - im Kurs sein – to be in the course

In your sentence we are talking about a situation inside the course (a location, not movement), so in + dem Kurs → dative → im Kurs.

Why does the sentence start with Im Kurs and not with Die Mehrheitsmeinung?

German main clauses are typically verb-second (V2), but the element in first position is flexible. You can move different parts to the front for emphasis or to set the topic.

All of these are grammatical:

Im Kurs ist die Mehrheitsmeinung, dass …
– Focuses on in this course (as opposed to somewhere else).
Die Mehrheitsmeinung im Kurs ist, dass …
– Focuses more on the majority opinion itself.
Dass diese Übung schwer ist, ist im Kurs die Mehrheitsmeinung.
– Fronts the whole dass-clause for strong emphasis on the content.

No matter what you put in first position, the finite verb (ist) must stay in second position in a main clause. Starting with Im Kurs is a stylistic choice to highlight the setting.

Why is Mehrheitsmeinung written as one word?

German loves compound nouns. Mehrheitsmeinung is a compound of:

die Mehrheit – the majority
die Meinung – the opinion

Together: die Mehrheitsmeinung – “the opinion of the majority”.

In German, we normally write such combinations as one word, not as two separate nouns. Some parallel examples:

die Hausaufgabe (Haus + Aufgabe) – homework
der Sprachkurs (Sprache + Kurs) – language course
der Fahrkartenautomat (Fahrkarte + Automat) – ticket machine

You could also say die Meinung der Mehrheit, which is correct, but die Mehrheitsmeinung is more compact and idiomatic in many contexts.

What gender is Mehrheitsmeinung, and how can I tell it uses die?

The gender of a German compound noun is determined by the last part (the head of the compound).

Mehrheitsmeinung → the head is Meinung
Meinung is feminine: die Meinung
Therefore: die Mehrheitsmeinung

A helpful pattern: most nouns ending in -ung are feminine:

die Zeitung, die Prüfung, die Bedeutung, die Entscheidung, die Übung, die Meinung

So die Mehrheitsmeinung is feminine singular nominative here.

Why is there a comma before dass, and what does dass do?

dass introduces a subordinate clause (a dependent clause). The structure is:

Main clause: Im Kurs ist die Mehrheitsmeinung
Subordinate clause: dass diese Übung schwer ist

In German, you must put a comma before most subordinate clauses, including dass-clauses. So the comma is obligatory.

dass here roughly corresponds to English that in sentences like:

“The opinion is that this exercise is difficult.”

It marks that the following clause is the content of the opinion.

In dass diese Übung schwer ist, why is ist at the end?

In subordinate clauses introduced by dass, the conjugated verb goes to the end of the clause. This is a key German word-order rule:

Main clause (V2):
Diese Übung ist schwer. – The verb ist is in 2nd position.
dass-clause (verb-final):
…, dass diese Übung schwer ist.

Pattern:

dass
- [subject] + [other elements] + [finite verb at the end]

Other examples:

…, dass er morgen kommt.
…, dass wir genug Zeit haben.
…, dass das Wetter heute schön ist.

Can I say dass diese Übung ist schwer instead?

No, that word order is wrong in standard German.

Once you introduce a clause with dass, you are in a subordinate clause, and the finite verb must go to the end:

✅ dass diese Übung schwer ist
❌ dass diese Übung ist schwer

Putting ist in the “second position” (like in a main clause) after dass is a common learner error, but native speakers will hear it as incorrect immediately.

What case is diese Übung, and why is it diese and not dieser or dieses?

Inside the dass-clause, diese Übung is the subject of the verb ist, so it’s in the nominative case.

Subject: diese Übung
Verb: ist
Predicate adjective: schwer

Übung is feminine, so the nominative singular of dies- is:

diese Übung (fem. nominative singular)
Compare:
- dieser Mann (masc. nom. sg.)
- dieses Kind (neut. nom. sg.)
- diese Kinder (plural nom.)

So here you get diese Übung because:

Case: nominative (subject)
Gender: feminine
Number: singular

What is the difference between schwer and schwierig here?

Both schwer and schwierig can mean “difficult”, and in many situations they are interchangeable. In this sentence, both of these are possible:

…, dass diese Übung schwer ist.
…, dass diese Übung schwierig ist.

Subtle tendencies:

schwer literally also means “heavy” and can feel a bit more physical or emotional:
- ein schwerer Koffer – a heavy suitcase
- eine schwere Entscheidung – a hard decision
schwierig is more strictly “difficult/complicated”:
- eine schwierige Aufgabe – a difficult task
- ein schwieriger Text – a challenging text

When talking about exercises, homework, tests, etc., both are very common. Learners can safely treat them as synonyms in this context.

Could I say the whole sentence in a different word order, and would the meaning change?

Yes, you can reorder parts of the main clause without changing the core meaning; you mainly change the focus. Some natural variants:

Im Kurs ist die Mehrheitsmeinung, dass diese Übung schwer ist.
– Highlights in the course (maybe contrasting with other groups).
Die Mehrheitsmeinung im Kurs ist, dass diese Übung schwer ist.
– Slightly more neutral, very typical structure: The majority opinion in the course is that …
Die Mehrheitsmeinung ist im Kurs, dass diese Übung schwer ist.
– Grammatically possible, but stylistically a bit odd; usually you’d attach im Kurs directly to Mehrheitsmeinung as in (2).

No matter the order in the main clause:

The verb in the main clause must remain second.
In the dass-clause, the finite verb (ist) must stay at the end.