Could you give me the accepted reason why  our churches  face the East.  In addition, in a lot of  our Ukrainian Orthodox cemeteries, the buried are facing the east as well.

It is a matter of symbolism as is so often the case in Eastern Christianity:

We face away from the darkness (west is where the sun sets) - towards the  light (it rises in the east). So it is with the orientation of our temples.

 So it is with the way we do Holy Mysteries of Baptism and Matrimony. The  bodies of our blessed dead are placed facing the east in the temple at a  funeral - except for priests and bishops who are placed facing the  congregation because by their deaths they are preaching their last earthly  sermon to the faithful. Thus when we bury our dead facing the East it is so  that they face the light.