Physical inequivalence

In 1907, Einstein wrote a long article on the special theory of relativity, "On the Principle of Relativity and the Conclusions Drawn from It", in which Einstein first mentioned the principle of equivalence, and since then, Einstein's ideas on the principle of equivalence have evolved. Based on the natural law that inertial mass and gravitational mass are proportional to the mass of inertia and gravitational mass, he proposed that a uniform gravitational field in an infinitesimally small volume can completely replace the reference frame of accelerated motion. Albert Einstein also put forward the idea of a closed box

The most common way to explain the equivalence principle is that the observer in a closed box cannot determine whether he is at rest in a gravitational field or in a space without a gravitational field in accelerated motion, and the equality of inertial mass with gravitational mass is a natural corollary of the equivalence principle.

Personally, I feel that non-equivalence is the inverse process of equivalence, for example: in electricity, the ammeter can be replaced by a wire, that is, the resistance is considered to be 0The voltmeter is considered an open circuit.

They have the same effect on the object, so they can be considered equivalent. However, some vectors are the same size, but they cannot be considered equivalent.

For example, the gravitational force of an object and the pressure on the support surface are generally considered to be equal, but they are not equivalent.

Size gravity g=mg

Pressure f=mg conditions: 1 support surface level 2 in the vertical direction only by gravity and support force and in equilibrium.

Point of effect. Gravity center of gravity.

Pressure contact surface.

Applying force to the object. Gravity Earth.

Pressure heavy loads.

Subjected to force. Gravity Heavy objects.

Pressure contact surface.

Quality. Gravity Gravity.

Pressure: Elasticity.

So gravity and pressure cannot be equivalent. Now, do you understand the non-equivalence?

For example, gravity and gravitation are not equivalent, which is physical inequivalence.

The basic principle is based on the experimental fact that gravitational mass is equal to inertial mass (see Ether Experiment). One of the foundations of the general theory of relativity. The direct corollary that the gravitational mass is strictly equal to the inertial mass is that the gravitational acceleration of any object is equal, and it shows that the gravitational field is different from other types of force fields such as electric fields, magnetic fields, etc., and that gravitational fields are equivalent to inertial force fields.

a.Einstein illustrated this with a hypothetical experiment with a lift. None of the physical experiments performed by the observer in this enclosed elevator could determine whether his frame of reference was an inertial frame with gravity or a non-inertial frame with no gravity but only rising with acceleration g relative to an inertial frame, in both cases he measured the acceleration of the free fall of the object after release is g, indicating that the motion of the object in the gravitational field is equivalent to the motion of the object in the non-inertial frame, or that the gravitational field is equivalent to the inertial force field.

Since gravity is different from gravity, the gravitational force at various points in space is unequal, and the gravitational field and the inertial force field are only equivalent in a small local area. Einstein built on the principle of equivalence and the principle of general relativity.