Lens Depth Distortion 

 - what happens to the width of the background when you go from WA to tele?

In Wide Angle the width is broader and on telephoto the wide is more compressed. 

          - what happens to the distance between the background & subject?

In wide angle the subject is further from the background and in telephoto the subject appears closer to the 

          - what happens to the subjects themselves in terms of expansion & contraction (for
            the width) as well as compaction and enlargement (for front to back)?

In wide angle the subject(s) expand and the width is very wide. From front to back the subject  enlarges and appears bigger. In telephoto the width is more compressed and the subject(s) compact and appear smaller.

  Scenario: imagine that you're shooting a model (full body) against a seamless. Your

  framing of the model is what you want but the edges (and beyond) of the seamless are

  visible in your frame. You don't want to move the model back towards the seamless and  

  you don't want to have to retouch out the seamless edges. Applying what you learned

  from this exercise today, what's the solution using just your camera & lens?

You (the photographer) would back up and zoom in (or use a telephoto lens.)

Wide Angle 

 18mm (28mm equivalent)

-standing 5 meters from subject

-back legs of stool are noticeable

-table distorted 

-back seamless is noticeable and appears small

-back wall distorted

-looks more 3-dimentionsal

Telephoto

 55 mm (80mm equivalent)

- stool looks more 2-dimentional

- seamless fills majority of frame

- seamless is much bigger

- hat appears slightly bigger

- table seems narrower

Wide Angle

18mm (equivalent to 28mm)

- model appears a bit distorted

- seamless is noticeable 

- model look farther from the seamless

Telephoto

55mm (equivalent to 80mm)
- model looks more compressed
- sides of seamless are not in frame
- model appears closer to the seamless