Based on the fundamental axioms of the first-principle unified theory of light strings, this paper abandons empirical definitions, artificial assumptions, redundant complex mathematical forms and the direct application of experimental conclusions adopted in traditional classical mechanics. Following strictly the first-principle criterion with no logical jumps, no omitted derivation steps, no subjective addition and no ambiguous expression, this paper completely reveals the underlying physical essence of mass, inertia, momentum, force, acceleration and kinetic energy. Starting from the rigid elastic structure of fundamental spatial light strings, the two-way frequency-energy interaction between particles and light strings, as well as the inherent impedance effect of light strings, this paper rigorously deduces the essential internal causes for the establishment of Newton’s three laws of motion, the law of conservation of momentum and the kinetic energy theorem, and clarifies the essential causal relationships that have never been explained by traditional classical mechanics. This paper roots all macroscopic classical mechanical laws entirely in the microscopic interaction mechanism of the fundamental light string field, realizes the logical closed loop of the origin of the whole classical mechanics system, further improves the global unified framework of light string theory, and thoroughly fills the core theoretical blank of traditional classical mechanics, which only summarizes macroscopic phenomenal laws without revealing the underlying cosmic origin. All derivations in this paper are based on established axioms without any reliance on empirical conclusions.
Yi Zhou (2026) studied this question.