Model answer Restaurant example
Diagrams

The first step is to identify the potential objects (green), and activities (pink). A selection of the objects forms the object model; a selection of the processes leads to the IDEF/SADT model.

The object model based on the identified (green) nouns [list of selected objects on the left side] could for instance look as follows:

This diagram also leads to a number of questions, with associated answers, see below:

The high-level SADT / IDEF-0 diagram for the case departs from the idea that a customer enters the restaurant, and leaves with a meal after having paid. The main process is termed "serve customer". Some of the potential resources have been identified in the object model. An example high-level diagram could for instance be:

If we work this out into a number of lower-level processes, using the pink verbs in the top scanned assignment, we get for instance:

Finally, cross-check that all the objects have been used in some way or another in the IDEF / SADT model, and that the IDEF / SADT model does not contain any terms that have not been introduced in the object model. This seems to be the case. By the way, multiple solutions for the diagrams, with varying levels of detail, are possible as a potentially good answer.