Na flecie trudno zagrać tę nutę tak dobrze jak na skrzypcach.

Because with many musical instruments, Polish normally uses the pattern grać na + locative.

So:

• grać na flecie = to play the flute
• grać na skrzypcach = to play the violin

This is just the standard idiom. It does not literally mean someone is physically on the instrument.

A few more examples:

• grać na pianinie
• grać na gitarze
• grać na trąbce

So in this sentence, na flecie and na skrzypcach are exactly what you would expect.

Because skrzypce is a plural-only noun in Polish. The instrument violin is grammatically plural, even though it refers to one instrument.

That means its forms are plural:

• nominative: skrzypce
• locative after na: na skrzypcach

This is something you simply have to learn with the word. Polish has a few nouns like this.

Trudno is an adverb/predicative form used in impersonal sentences like:

• Trudno zrozumieć
• Trudno uwierzyć
• Trudno zagrać tę nutę

This structure means it is hard to...

By contrast, trudny / trudna / trudne are adjective forms and must describe a noun:

• To jest trudna nuta = This is a difficult note
• To jest trudne zadanie = This is a difficult task

So:

• trudna nuta describes the note
• trudno zagrać tę nutę describes the action of playing it

In present-tense Polish, jest is often omitted, especially in very common patterns like this one.

So:

• Trudno zagrać tę nutę
  and
• Jest trudno zagrać tę nutę

both make sense, but the version without jest is more natural here.

The structure trudno + infinitive is extremely common and usually does not need jest.

Zagrać is perfective, while grać is imperfective.

Here, zagrać tę nutę focuses on successfully producing one specific note, as a single completed act. That is why perfective zagrać sounds natural.

Compare:

• trudno zagrać tę nutę = it is hard to play/get out that note
• trudno grać na flecie = it is hard to play the flute, more generally

So zagrać fits because the sentence is about one particular result: playing that note well.

Because nuta is the direct object of zagrać, so it goes into the accusative case.

The noun is feminine:

• nominative: ta nuta
• accusative: tę nutę

So:

• Ta nuta jest trudna = This note is difficult
• Trudno zagrać tę nutę = It is hard to play this note

A useful extra point: in everyday speech, many Poles say tą nutę, but standard written Polish prefers tę nutę.

It means as well as or more literally as well as on the violin.

This is a standard comparison pattern:

• tak + adverb + jak
• tak dobrze jak = as well as

So the sentence compares the quality of playing the note on two instruments.

You could also say równie dobrze jak, which is very close in meaning:

• Na flecie trudno zagrać tę nutę równie dobrze jak na skrzypcach.

But tak dobrze jak is perfectly normal.

The comparison is about how well that note can be played on the flute versus on the violin.

So the idea is:

• on the flute, it is hard to play that note
• to the same quality
• as on the violin

In other words, the level of performance is being compared, not the instruments in some general abstract way.

Polish word order is flexible, and starting with Na flecie puts the flute in focus right away.

It gives the sentence a contrastive feel, something like:

• As for the flute, it is hard...
• On the flute, it is hard...

A different order is also possible, for example:

• Tę nutę trudno zagrać na flecie tak dobrze jak na skrzypcach.

That version is grammatical too, but it shifts the emphasis slightly. The original sentence foregrounds the flute as the main point of comparison.

Yes. Polish often adds a dative pronoun to show who experiences the difficulty.

For example:

• Trudno mi zagrać tę nutę na flecie. = It is hard for me to play this note on the flute.
• Trudno mu zagrać tę nutę na flecie. = It is hard for him to play this note on the flute.

So the original sentence is impersonal and general, but you can easily make it personal by adding mi, ci, mu, jej, nam, wam, im, and so on.