A kinetic-energy-based approach to modeling unsteady forces on an accelerated sphere is implemented for the purpose of fluid velocity extraction with non-Stokesian tracer particles. An expression for the force due to the energized-mass concept of Galler et al.(under review) is developed, with contributions due to rate of shear-layer growth and quasi-steady drag. The model exhibited strong agreement with 2D particle image velocimetry and direct force measurements performed for two cases of an accelerated sphere. The dynamic model was applied to the case of a non-ideal particle responding to a velocity perturbation, with a relative velocity between the body and fluid. Compared to the velocity response predicted by conventional force models, the energized mass model resulted in additional force, and therefore greater acceleration, during the change in fluid velocity. The relaxation to steady state was then slowed due to the relative acceleration between the body and steady flow.