Final answer:
The dynamic diagram among the options is the object diagram. Other options like the use-case, package, and class diagrams are static. In a free-body diagram, the object is represented as a point.
Step-by-step explanation:
You asked which diagram is considered dynamic. Among the options provided, the object diagram is considered a dynamic diagram. In software engineering, dynamic diagrams are used to show the behavior of a system over time. An object diagram is a snapshot of the instances in a system at a particular moment, which can display the state of the system and the interaction between objects at that point in time. Other diagrams, like the use-case, package, and class diagrams, are static and do not represent the system's behavior over time.
In contrast to a dynamic object diagram, a free-body diagram in physics represents forces acting on an object. In such a diagram, the object of interest is typically represented by a single point and the forces are represented as vectors radiating from the point. This simplifies the representation of forces and makes it easier to analyze the effects on the object.
To address the information in your question, in a free-body diagram, the object is typically represented as a point, as mentioned in some of your statements. This point acts as a simplified representation of the object in question, and vectors are used to represent the various forces acting upon it.