2. Special Theory of Relativity: S(R4, η _ α β)

3. Relative velocity formula: △ v = | v1-v2 |/√ (1-v1v2/C2).

4. The relative length formula L = LO * √ (1-V 2/C 2) LO.

5. The relative mass formula m = mo/√ (1-V 2/C 2) mo.

6. Relative time formula T = to * √ (1-V 2/C 2) to

7. mass-energy equation E = MC 2

Relativity is a theory about space-time and gravity, mainly founded by Einstein, which can be divided into special relativity and general relativity according to different research objects. The introduction of relativity and quantum mechanics has brought revolutionary changes to physics, which laid the foundation of modern physics. Relativity has greatly changed the common sense concepts of the universe and nature, and put forward new concepts such as "simultaneous relativity", "four-dimensional spacetime" and "curved spacetime".

However, in recent years, people have a new understanding of the classification of physical theories-to divide classical and non-classical physics according to whether their theories are deterministic, that is, "non-classical = quantum". In this sense, relativity is still a classical theory.

Extended data:

The difference between special relativity and general relativity

Traditionally, at the beginning of Einstein's theory of relativity, people used whether the question under discussion involved a non-inertial reference system as a symbol of the classification of special and general relativity. With the development of the theory of relativity, this classification method shows its shortcomings more and more-the frame of reference is related to the observer, and it is considered that dividing the physical theory with such a relative physical object cannot reflect the essence of the problem.

At present, it is generally believed that the difference between special relativity and general relativity lies in whether the problems discussed involve gravity (curved space-time), that is, special relativity only involves those problems that have no gravity or gravity can be ignored, while general relativity discusses physics with gravity. In the language of relativity, the background space-time of special relativity is flat, that is, the four-dimensional ordinary flow pattern matches Min scale, and its curvature tensor is zero, which is also called Min space-time; The background space-time of general relativity is curved, and its curvature tensor is not zero.

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