Learn Farsi: من سوار چرخ‌وفلک نمی‌شوم، زیرا ارتفاع آن ترسناک است. - I do not get on the Ferris wheel, because its height is scary.

Yes, it is! زیرا (zirâ) means because and connects two clauses just like چون (chon). The difference is mostly in register: زیرا is a bit more formal and is used more often in writing, whereas چون is very common in everyday speech. Notice that it is followed by the normal present indicative tense in the second clause, است (ast), not the subjunctive.

Why does the Farsi sentence use نمی‌شوم (nemi-shavam) for I do not get on?

In Farsi, to get on or to ride a vehicle is expressed with the compound verb سوار شدن (savâr shodan), which literally means to become a rider. Here, it is in the negative present indicative form: نمی‌شوم (nemi-shavam, I do not become). So سوار چرخ‌وفلک نمی‌شوم literally means I do not become a rider of the Ferris wheel.

What are the parts of the word چرخ‌وفلک (charkh-o-falak)?

It is a fun compound word! چرخ (charkh) means wheel and فلک (falak) means sky or heavens. The ـوـ (-o-) in the middle means and. So a Ferris wheel in Farsi is poetically called a wheel and sky.

Instead of ارتفاع آن (ertefâ'-e ân) for its height, could I use the possessive ending ارتفاعش (ertefâ'-ash)?

Yes, absolutely! ارتفاعش (ertefâ'-ash) means its height and is very natural, especially in spoken Farsi. Using ارتفاع آن (ertefâ'-e ân), which literally means the height of that, is just a slightly more formal or emphatic way to say the exact same thing. This matches the slightly formal tone of (zirâ) used in this sentence.