Is Zakah(obligatory charity) due on the equipments 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.

Am I permitted to perform more than one prayer within single ablution?

All perfect praise be to Allah, The Lord of The Worlds, and may His Peace and Blessings be upon our Prophet Muhammad and upon all of his family and companions.

You are permitted to pray as many as you could within one ablution and to recite Quran so long as your ablution isn't nullified. And Allah Knows Best.

Should one fulfill his vow of donating an animal to the poor and needy with one sheep although he had repeated the vow several times?

Each vow has to be fulfilled, and repeating the words of the same vow for confirmation renders its fulfillment obligatory as one vow. As for multiple vows, they have to be fulfilled as well.

What is the ruling on using bank cards such as Visa and MasterCard?

All perfect praise be to Allah, The Lord of The Worlds, and may His Peace and Blessings be upon our Prophet Muhammad and upo all of his family and comapnions.

It is permissible to use such cards in accordance with the following conditions : 1- The issuing body does not stipulate collecting interest upon late payments. 2- The merchant does not increase the price of the goods due to an increase in the commission collected from him by the card issuer.3- The purchased item(s) should not be gold , silver or currency in case the card is not covered. And Allah Knows Best.