In this study, we extend previously established results of relativized Newtonian dynamics—originally derived for inertial rectilinear motion—to the context of a uniformly rotating disk. Our findings reveal the presence of a nonluminous component coexisting with the luminous component, with the ratio of their radial densities being solely dependent on the rotation velocity.We apply these results to investigate the dynamics of both luminous and nonluminous matter in a diverse sample of 52 galaxies from the Spitzer Photometry & Accurate Rotation Curves (SPARC) dataset. For each galaxy, we calculate the radial density distributions of both matter components using only the measured rotation curves. The predicted radial density profiles of the nonluminous components closely trace the observed rotation curves for all tested galaxies.Our analysis indicates that the nonluminous component begins to dominate over the luminous component at rotation velocity of approximately V_flat/3. At rotation velocities approaching V_flat, the luminous component nearly vanishes, with the majority of the matter being nonluminous. The nonluminous component is expected to strongly dominate in all tested galaxies, with a fraction (0.757 ≤ f_NLM ≤ 0.990, σ_(f_NLM )= 0.0137).Moreover, consistent with the Radial Acceleration Relation (RAR), the correlations between the estimated total masses of the luminous and nonluminous components, and between the luminous component and the total dynamical mass, are very strong (r = 0.947 and 0.954, respectively). Additionally, in agreement with the Baryonic Tully-Fisher Relation (BTFR), the correlation between the total luminous mass and V_flat is also substantial (r = 0.626).These results suggest that key features typically attributed to exotic dark matter particles in galactic halos can be accounted for by simple relativistic considerations.