Final answer:
The initial step in structural analysis using the force method involves defining the system of interest and creating a free body diagram to visualize all external forces.
Step-by-step explanation:
The first step in analyzing a structure using the force method is to determine the system of interest and draw a free body diagram. The free body diagram is essential as it visualizes all external forces acting on the system, which can be crucial for understanding the reaction forces and moments. It's only after this step that other principles, such as Hooke's Law or calculations related to bending stress, come into play.