What is the ruling on reciting the Chapter after Al-Faatihah , and what should a worshiper who forgets it do?

All perfect praise be to Allah, The Lord of The Worlds.                                                                                                                                                                  Any other part of Qur'an that a worshiper reads after Al-Faatihah during the first and the second Rak`ahs is a Sunnah, and forgetting to do so doesn`t nullify prayer, and doesn`t require performing Sujood As-Sahw (prostration of forgetfulness). And Allah Knows Best.

Is it permissible for the guardian, or the father of the child to hit the latter in order to teach him/her good manners?

It is permissible for the guardian to hit his/her child for teaching them good manners once they become ten years old provided that it is done mildly, harmlessly and without intimidation. Actually, such punishment is to be employed gradually i.e. after: asking, warning, and scolding. As for the teacher, he isn`t allowed to hit the student unless the latter`s father approves of it, and it is done according to necessity without intimidation, or harm.

What should one who made an intention, at night, to make up for a missed fasting day, but broke his fast on the next day?

One who started making up a missed fasting day, then broke his/her fast without a legitimate reason is considered sinful, and is only obliged to make up for the missed fasting days. And Allah Knows Best.

I have 490 shares in a commercial company, and they have been held for a year. The price of each share is one dinar, noting that the shares are at a loss. I want to know the amount of zakat due on them?