Can someone who begins a voluntary fast break it?
It is preferable for someone who begins an act of worship not to break it.
Allah the Exalted has said {what means}: "and let not your [good] deeds come to nought!" [Muhammad/33].
However, if a person starts a voluntary fast (nafl) and needs to break it, they are going against what is preferable, but there is no sin upon them.
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 Islamic ruling on eating from the 'aqīqah?
All praise is due to Allah, and may peace and blessings be upon our Master, the Messenger of Allah.
It is recommended (mandūb) to eat from the 'aqīqah, unless it was vowed (mandhūrah). If the 'aqīqah was made as a vow, then it is prohibited to eat from it, and it becomes obligatory to distribute the entirety of it in charity to the poor. And Allah Almighty knows best.
What is the ruling on offering a sheep as a sacrifice (Udhiyah) if its fat-tail is sound, except that when it was young, the tip of its fat-tail was cut so that it would grow larger? And what is the ruling in case of doubt regarding the amount that was cut?
In the Name of Allah, and may peace and blessings be upon our Master, the Messenger of Allah.
Cutting a minor, insignificant portion from the tip of an animal's fat-tail (al-alyah) to encourage it to grow larger is not considered a defect, and it does not prevent the animal from being valid for sacrifice (Udhiyah).
It is stated in Tuhfat al-Muhtaj (Vol.9/P.352): "There is some scholarly deliberation regarding the common practice of cutting the tip of the fat-tail so that it grows larger. It could potentially be likened to a partial cut of the ear—supported by the jurists' general rule: 'even if it is a small amount.' On the other hand, if it is an exceptionally minor cut, it might have no effect on validity. This is explicitly clarified by the juristic exception to the general rule, which states that cutting a tiny piece from a large limb causes no harm. This latter view is more well-founded.
Furthermore, I found that some scholars investigated this matter and concluded: 'It should not affect validity if a custom-sanctioned portion of its fat-tail is removed during its youth to make it grow larger and look better, just as castrating a male animal causes no harm.' However, applying this unconditionally contradicts the established texts of the jurists, as understood from what I have laid out; thus, the restriction I specified is what must be relied upon."
Similarly, it is mentioned in Nihayat al-Muhtaj (8/135): "If a small piece is cut from the fat-tail to help it grow larger, the most well-founded view is that the sacrifice remains valid, as was given in a formal legal verdict (Fatwa) by my father [Shihab al-Din al-Ramli], may Allah be pleased with him. This is proven by the jurists' maxim: 'The loss of a tiny piece from a large limb causes no harm.'"
In cases where there is doubt as to whether the portion cut was large or small, the animal is still deemed valid for sacrifice. It is noted in Hashiyat al-Shubramallisi ‘ala Nihayat al-Muhtaj (Vol.8/P.135):
"This matter requires careful consideration, but the closer and more correct view is that it is valid. This is because soundness is the default state for the animal from which the piece was cut, and it aligns with what usually occurs—namely, that the part removed to help the fat-tail grow larger is naturally very small." And Allah the Almighty Knows Best.