This paper put forward a simple deduction method of the particle-energy relationship formula: from Lorentz transformation and wave-particle duality and from the phase constance of wave function Under Lorentz transformation, we deduced the dynamic formula and energy trsnsformation formula, and in turn, deducing the particle-energy relationship formula and particle-velocity relationship formula.

Based on the laws of energy conservation and momentum conservation, the mass-speed equation is derived through Lorentz transformation.

Inquiry of experimental basis of mass-velocity relation;

The coordinate transformation about the classical electromagnetic mass has been researched, and the ‘intrinsic’ motion in the space where the energy flux density are equal to zero are discovered The mass-velocity relation of the electromagnetic mass of charged particle is discussed, and the results are the same as those obtained by the method on the particle collisio

This paper, from phase non-changeability, deduced the mass-energy relation formula and mass-velocity relation formula, different from conventional method in the textbooks, which are simple and easily accepted by the students.

Two speed-density relations are worked out based on the analysis of traffic flow,thus two important critical parameters,namely,the free flow speed and the jamming density are determined.