Difference between うら and 後ろ

Question

What is the difference between these two words? My teacher has listed a few examples of each:

紙の裏{うら} • ビルの裏 • 裏ゲート

後ろの席 • Aさんの後ろ

My hypothesis is that 裏 refers to a surface (such as paper, building) while 後ろ refers to the three-dimensional space behind an object (such as seats in a theatre, space behind a person) Is this accurate?

After trying to read an answer on a Japanese forum, I found myself more confused; 車の裏 can mean the bottom of the car, and ビルの裏 refers to the side opposite the entrance whereas ビルの後ろ refers to the side opposite the place where the speaker stands / is talking about. Are there any general rules to explain when 裏 means bottom, or when 裏 and 後ろ change depending on point of view?

Link to forum: http://sp.okwave.jp/qa/q7795599.html

Answer 1

裏 means the opposite side of surface or the field that belongs to that aspect extensionally a zone that lies in front of that aspect while 後ろ means backward of something when objects or spaces are put in a row in order.

In other words, when the target object doesn't have linguistically recognizable surface, 裏 doesn't make sense, and when the surface runs vertically (and when you take the nearer object in your perspective as 前), 裏 overlaps 後ろ. When the surface runs horizontally, 裏 overlaps 上 or 下 like the example of a car, in which 後ろ usually doesn't coincide with 裏.

In addition, 裏 usually implies the side invisible from your perspective.

Answer 2

裏 means "back". The opposite of 裏 is 表 which means "front".
裏(ura): back
表(omote): front

裏 and 表 are used for objects that have 2 sides, one being the front, the other being the back.
So you can say ビルの裏, because a building usually has a front and back sides.
But you cannot say 木の裏, since a tree doesn't have a back or front side.

後ろ means "behind". The opposite of 後ろ is 前
後ろ (ushiro): behind
前 (mae): front

You can say 木の後ろ meaning "behind the tree".
木の前 means the space between you and the tree.