Kodehjulet åpner låsemekanismen.

Because Norwegian very often forms compound nouns by joining words together.

• kodehjulet = kode
  • hjul
    • the definite ending
• låsemekanismen = lås
  • mekanisme
    • the definite ending

This is much more common in Norwegian than in English. Where English might write code wheel or locking mechanism, Norwegian usually writes them as one word.

Those are the definite singular endings attached to the nouns.

• et kodehjul = a code wheel

• kodehjulet = the code wheel

• en låsemekanisme = a locking mechanism
• låsemekanismen = the locking mechanism

The endings are different because the nouns have different grammatical genders:

• kodehjul is neuter → definite singular -et
• låsemekanisme is masculine/common → definite singular -en

So Norwegian often puts the at the end of the noun instead of using a separate word like English does.

Because in Norwegian, the definite article is usually attached to the noun as a suffix.

So instead of saying:

• the code wheel
• the locking mechanism

Norwegian says:

• kodehjulet
• låsemekanismen

That is the normal way to make a noun definite in a simple sentence like this.

The dictionary form is å åpne, which means to open.

• å åpne = infinitive
• åpner = present tense

So Kodehjulet åpner låsemekanismen uses the present tense, meaning something like The code wheel opens the locking mechanism or opens up the locking mechanism.

Because Norwegian verbs usually do not change for person the way English verbs sometimes do.

For example, in Norwegian:

• jeg åpner = I open
• du åpner = you open
• han åpner = he opens
• de åpner = they open

The verb form åpner stays the same. This is simpler than English, where you have a special form like opens for he/she/it.

In a normal Norwegian main clause, the usual word order is:

Subject + Verb + Object

So in:

Kodehjulet åpner låsemekanismen

• kodehjulet = subject
• åpner = verb
• låsemekanismen = object

In other words, the code wheel is doing the action, and the locking mechanism is receiving the action.

Yes. A passive version would be:

Låsemekanismen åpnes av kodehjulet.

That means The locking mechanism is opened by the code wheel.

Compare:

• Kodehjulet åpner låsemekanismen. = active
• Låsemekanismen åpnes av kodehjulet. = passive

The original active sentence is usually more direct and natural unless you especially want to focus on låsemekanismen.

It would be:

Et kodehjul åpner en låsemekanisme.

That means A code wheel opens a locking mechanism.

Compare:

• et kodehjul = a code wheel

• kodehjulet = the code wheel

• en låsemekanisme = a locking mechanism
• låsemekanismen = the locking mechanism

So the sentence you were given is definite: it refers to a specific code wheel and a specific locking mechanism.

This is another example of a Norwegian compound noun.

• lås = lock
• mekanisme = mechanism

Together, låsemekanisme means locking mechanism or lock mechanism.

This kind of structure is very common in Norwegian. The first part describes the second part.

So:

• låsemekanisme = a mechanism related to a lock
• kodehjul = a wheel related to a code

The letter å is a separate letter in Norwegian, not just an a with a mark on it.

In åpner, å is pronounced roughly like the vowel in British English law or more, though the exact sound depends on dialect.

A few useful points:

• å is always its own letter in the alphabet
• å åpne starts with that sound
• the å sound is different from a

So åpner should not be read like English apener or opener.

In many Norwegian pronunciations, the h in hj is silent or nearly silent, so hjul sounds roughly like yool to an English speaker.

So:

• hjul = wheel
• hjulet = the wheel

This can be surprising for English speakers because the spelling suggests a strong h, but in standard pronunciation the sound is much closer to jul/yul.

It is a perfectly normal kind of Norwegian formation. Even if a specific compound is technical or context-dependent, the way it is built is completely natural.

Norwegian freely creates compounds like:

• sykkelhjul = bicycle wheel
• tannhjul = gear wheel
• kodehjul = code wheel

So even if the exact object is technical, the structure of the word is very Norwegian.

It can do either, depending on context.

The present tense åpner can mean:

• something happening now: The code wheel is opening the locking mechanism
• a general fact or function: The code wheel opens the locking mechanism

In technical descriptions, Norwegian often uses the present tense for general function, just like English does. So in many contexts this sentence sounds like a description of how a device works.