Moving objects are currently represented in databases by means of an explicit representation of their trajectory. However from a physical point of view, or more specifically according to Newton’s second law of motion, a moving object is fully described by its equation of motion. We introduce a new data model for moving objects in which a trajectory is represented by a differential equation. A similar approach is taken in computer animation where this is known as physically based modeling. We give a query language for our data model and use techniques from physically based modeling to evaluate queries in this language.