Junior high school physics has Newton's first law, the law of light reflection, and? The laws of refraction, conservation of energy, current and ohm of light are analyzed as follows:

Newton's first law, also known as the law of inertia, contains the following contents: all objects always keep still or move in a straight line at a constant speed when they are not affected by external forces; Law of light reflection: one side, two sides and three dimensions. The angle between the incident light and the normal is the incident angle. The include angle between that reflected light and the normal is the reflect angle; The law of refraction of light: one side, two sides, three sides, big four empty;

Law of conservation of energy: energy will neither be produced out of thin air nor disappear out of thin air, but will only be transformed from one form to another, or from one object to another, and the total amount of energy will remain unchanged; Current law: electric quantity q, voltage u, resistance r; The formula of ohm's law: I=U/R, U=IR, r = u/I;

Therefore, we can see that junior high school physics has Newton's first law, light reflection law, light refraction law, energy conservation, current, ohm's law and so on.

Physical laws derived from the principle of symmetry

Many basic laws of physics are the results of various symmetrical mathematics of time, space or other nature. In particular, some of Newton's conservation laws are related to some symmetry; For example, the conservation of energy is the result of symmetry of time motion (it is the same at any time in time), while the conservation of momentum is the result of symmetry (uniformity) of space (there is no special point in space).

The indistinguishability of all particles of various basic types (such as electrons or photons) leads to Dirac and Bose quantum statistics, which leads to the Pauli exclusion principle of fermions. The rotational symmetry of time and space coordinate axes (taking one as imaginary axis and the other as real axis) leads to Lorentz transformation. And then get the special theory of relativity. The symmetry of inertial mass and gravitational mass leads to general relativity.