"A physical model (in physics) is a representation of structure in a physical system and/or its properties." [David Hestenes]. A physical model will describe the system, the state of its constituents (including geometric and temporal structure), their internal interactions, external interactions, and the changes of state (that is to say, the system's patterns of behavior).
Physical models combine the definitions, concepts, procedures, interactions, laws of nature and other relationships that model some particular behavior or pattern found in the physical world. Cognitively, a physical model is a mentally-linked collection of physical laws, concepts, equations, and associated representations and descriptions that relate to a particular common pattern found in nature.
Models can be as broad as a law of nature, which are fundamental relationships among abstract quantities (for example, F = ma or the conservation of energy). While the laws of nature apply to anysituation in the real world, most models in Mechanics are much more specialized and concentrate on a single concept, a common pattern or a situation (for example, uniform circular motion), highlighting the relevant physical laws and how they apply to this type of situation. Models generally include several representations, each of which is a different way to conceptualize the model's applicability and implications. (For example velocity can be represented as an algebraic function of time, a graph of position vs. time, or a strobe picture of a moving object.) The modeler's mind will typically recognize immediately when aspects of a particular physical situation are similar to one of these representations, and will be ready to apply other representations and features of the model to this situation. The model's different aspects are then "activated" and hopefully one or two will give intuitive insight and another will lead to a solution (often analytic or numerical).