Is Zakah (obligatory charity) due on the items used in the trading process such as: cars , shops etc..?
No Zakah is due on equipments used in the trading process such as cars and the like.
What is the ruling on giving Zakah (obligatory charity) to one`s relatives?
It is impermissible to pay Zakah to one`s origins (parents and grandparents) because providing for them is an obligation on their branches (sons and daughters) if they were poor, but it is permissible to give some of the Zakah money to relatives whose provision isn`t due on the giver of the Zakah.
What is the ruling on buying a car from someone for less than the market price, because they are in a hurry to travel and want to sell their belongings at a lower price due to their urgency?
Yes it is permissible; however, a Muslim shouldn't take advantage of other's difficult situations.
My husband has deprived me of visiting my family and is threatening to take my 7-month-old baby girl. Is he entitled to do so?
All perfect praise be to Allah the Lord of the Worlds. May His peace and blessings be upon our Prophet Mohammad and upon all his family and companions.
Your question is unclear, but family visitation is a legitimate right of yours. However, if he deprives you from this, try to convince him with wisdom and fair preaching. If there is a problem between you two, try to fix it. As for your daughter, you are most entitled to her custody anyway. Even if he divorced you, the girl remains under your care so long as you don`t get married. And Allah The Almighty Knows Best.