Войлочная шапка защищает голову.

Because шапка is a feminine singular noun, and the adjective has to agree with it in gender, number, and case.

• войлочный = masculine
• войлочная = feminine
• войлочное = neuter
• войлочные = plural

So:

• войлочная шапка = a felt hat

This kind of agreement is a basic rule in Russian.

Because голову is the accusative singular form of голова.

In this sentence, голову is the direct object of the verb защищает (protects), so Russian uses the accusative case.

• голова = nominative, used for the subject
• голову = accusative, used for the direct object

So Russian is literally structured as:

• Войлочная шапка = the felt hat / a felt hat
• защищает = protects
• голову = the head

The subject is войлочная шапка because it is in the nominative case and the verb agrees with it.

You can spot it this way:

• шапка is nominative singular
• защищает is 3rd person singular
• голову is accusative, so it is the object

So the sentence means that the hat is doing the protecting, and the head is receiving the action.

Защищает is:

• present tense
• 3rd person
• singular
• from the verb защищать (to protect, imperfective)

So it means:

• he/she/it protects
• or more generally protects

Because the subject is шапка (hat), the verb is singular:

• шапка защищает = the hat protects

Russian does not have articles like the or a/an.

So войлочная шапка can mean:

• a felt hat
• the felt hat

The exact meaning depends on context.

In a standalone sentence like this, English often has to choose one, but Russian does not mark that difference with an article.

Войлочная means made of felt or felt.

It comes from the noun войлок (felt, the material).
The adjective войлочный / войлочная / войлочное means felt, made of felt.

So:

• войлочная шапка = felt hat

This is very common in Russian: a noun for a material becomes an adjective describing what something is made of.

Yes, Russian word order is more flexible than English because case endings show grammatical roles.

The neutral, most straightforward order here is:

• Войлочная шапка защищает голову.

But other orders are possible, for example:

• Голову защищает войлочная шапка.

That can shift the emphasis, but the meaning is still clear because:

• шапка is nominative
• голову is accusative

So case endings matter more than word order.

This is a normal pattern for many feminine nouns ending in -а.

For a noun like голова:

• nominative singular: голова
• accusative singular: голову

So the ending -а changes to -у.

More examples:

• мама → маму
• книга → книгу
• рука → руку

Since голова is the direct object here, it takes that accusative ending.

Yes. Защищает comes from the imperfective verb защищать.

That usually suggests:

• a general fact
• a repeated action
• an ongoing process

So this sentence sounds like a general statement: a felt hat protects the head.

If you used a perfective form, such as a future form of защитить, the meaning would shift more toward a single completed act, like will protect.

So the imperfective fits well for a general truth or function.

The main stresses are:

• во́йлочная
• ша́пка
• защища́ет
• го́лову

A rough pronunciation guide:

• во́йлочная ≈ VOYL-ohch-na-ya
• ша́пка ≈ SHAP-ka
• защища́ет ≈ zuh-shi-SHA-yet
• го́лову ≈ GO-luh-voo

A useful thing to notice is that stress in Russian can move:

• голова́
• but го́лову

That kind of stress shift is very common in Russian nouns.

Usually шапка means a hat/cap, often a warm or soft hat, especially in everyday Russian.

It is broader than one exact English word. Depending on context, it might be translated as:

• hat
• cap
• beanie
• winter hat

Here, because it is войлочная (felt), hat is a natural translation.

So шапка is a general everyday word, and the adjective gives you the material or type.

Grammatically, yes, but it would sound incomplete in most contexts unless the object is already obvious.

Russian often omits things that are understood from context, but in a general statement like this, keeping голову makes the meaning clear:

• Войлочная шапка защищает голову.

Without голову, the listener may wonder:

• protects what?

So in this sentence, the object is naturally included.