Various masaail of Salaah

Q: I accidentally put my prayer mat over a bone that my cat ate and I prayed over it. The bone was from halaal meat. Is this ok?

Q: I prayed zuhr and Asr salaah in a masjid which had a tomb in a seperate room besides the praying hall, but there was a window in the praying hall through which the tomb was visible. Will I have to repeat my prayer?

Q: Can I perform namaz after applying medicine on my penis? The oil is a medicine which was prescribed by the doctor.

Q: Is the ruling of 'weed' the same as khamar in the sense that if smoked, prayers are not accepted for 40 days? 

Q: How should a new Muslim perform salaah if he/she does not know any verses of the Holy Qur'aan?

Q: If someone doesn’t usually pray and just prays in front of people because if he doesn’t people will mock him, is it major shirk?

Q: Is it permissible to perform salah in a room in which a child is changing?

Q: What is the procedure of doing binaa in salaat? Do you have to go back to the same place in Haram or is it ok to read from anywhere in the Haram once you have redone your wudhu.

And how do you rejoin the salat, in which rakaat etc in the situation where the imam has already finished?

Q: Is salaah valid if a person does not remove his pubic hairs for more than 40 days?

Q: Is it permissible to use or prescribe sleeping pills? After using them, sometimes one is not in his conplete sense and sometimes says what will not usually say in public? Would Namaz be valid in this state? Can it be used if one is unable to sleep? Or can it be used sometimes when one wants to releive himself of worries?