NEWTON’S CRADLE AS CALIBRATED IMPULSE AND ELASTIC-MODE TRANSFER Momentum Conservation, Contact-Wave Propagation, Directional Constraint, and Resonance Unity in USP Field Theory Newton’s cradle is often presented as a simple demonstration of momentum and energy conservation. This paper develops a deeper operational description in which the transfer occurs through a finite sequence of pendulum loading, impact impulse, elastic compression, stress-wave propagation, collective modal response, and directional release. The balls are not perfectly rigid. During contact, they deform by a small amount and temporarily store part of the incoming energy as elastic strain. The resulting contact pulse has a measurable duration, force profile, impulse, and frequency content. The framework therefore treats the cradle as a loading–locking–release system: Loading stores gravitational or mechanical energy. Locking temporarily stores that energy in contact deformation and coupled elastic geometry. Release redistributes the stored energy into directed output motion, internal vibration, sound, support motion, rotation, and heat. The paper defines measurable quantities including contact time, impulse, directional transfer efficiency, transverse leakage, elastic-energy distribution, modal compatibility, damping, and sensor response. A dimensionless resonance-unity index is introduced to measure temporary phase organization across selected mechanical modes: U_R(t) = |Σ w_j exp(iφ_j) / Σ w_j| Values near one indicate concentrated phase organization, while lower values indicate broader phase dispersion. The central experimental question is whether this measured phase organization improves prediction of directional energy transfer after standard mechanical variables—such as release energy, restitution, alignment, damping, contact duration, and suspension geometry—have already been included. The framework preserves classical mechanics, momentum conservation, energy conservation, Hertz-type contact mechanics, elastic-wave propagation, and normal-mode analysis. USP Field Theory is used as an operational geometry-and-timing interpretation rather than as a replacement for established mechanics. Full paper: https://zenodo.org/records/21453912 #NewtonsCradle #ClassicalMechanics #ElasticWaves #USPFieldTheory #PhysicsResearch - @sadeghsep