Extended Classical Mechanics: Observational Reinterpretation of the Coma Cluster

This study applies the Extended Classical Mechanics (ECM) framework to the Coma galaxy cluster, presenting an observationally constrained reconstruction of local gravitational dynamics through the negative apparent-mass formalism. Retaining the classical weak-field dynamical structure while replacing the ΛCDM dark-energy ontology, the work reformulates mass density profiles, effective gravitating mass, radial acceleration fields, and the zero-gravity boundary within ECM's signed effective-mass dynamics. Utilizing established observational constraints from gravitational mass estimates and matter-density profiles, the analysis demonstrates how the negative apparent-mass sector and its corresponding density yield repulsive local acceleration and a well-defined equilibrium radius without invoking cosmological-constant vacuum energy or spacetime curvature. The treatment further contextualizes this observational application within the broader ECM research program, establishing continuity with prior equilibrium reinterpretations while extending the formalism toward testable density-dynamical predictions.