If we analyze the motion law of free fall from Newton's law of universal gravitation, any two objects follow the law of universal gravitation, and two objects with different weights will get the same acceleration when they fall freely in the earth's gravitational field, so the experimental results show that it is in line with the law of universal gravitation for two balls to land at the same time. In other words, Galileo's experimental conclusion is completely consistent with the theoretical analysis made from the law of universal gravitation. From this point of view, Galileo's experiment is correct. But the law of universal gravitation needs certain conditions to be fully established. It must be assumed that the interaction between any two neutral objects completely conforms to the law of universal gravitation, and the action law of any two object fields is exactly the same as that of the ground field, but this is not the case.
The formula of gravity acceleration can be derived from Newton's law of universal gravitation.
When the object above the earth describes its motion with the center of the earth as the reference point, it moves around the earth in a uniform circle. The resultant force received by an object in the direction connected with the center of the earth is the centripetal force pointing to the center of the earth. This centripetal force is provided by the gravity between the object and the earth, that is, F direction = F million. According to Newton's second law formula followed by centripetal force: F=mg and the law of gravity formula: available,
(When R>& gt is small)
In the above formula, m is the mass of the earth, m is the mass of the object, r is the radius of the earth, h is the height of the object from the ground, g is the centripetal acceleration generated by the uniform circular motion of the object around the earth, that is, the gravitational acceleration of the object here, and g is the gravitational constant.
Let's take a look at the free fall of objects above the ground. In this case, the gravity of the earth on the object is greater than the centripetal force required for the object to make a uniform circular motion around the earth at this position, so the object will be in a state of free fall. The resultant force on the free fall of an object is still: f = F million.
It can be seen from the formula of gravity acceleration of objects deduced above that the gravity acceleration of two objects with the same height from the ground is exactly the same regardless of their mass, size, structure and density.
Because according to the law of interaction between fields, the gravitational interaction between objects actually works with the help of fields between objects. Similarly, the attraction between any two objects and the earth also works with the help of the field. Only when the gravitational interaction between any two objects and the golf course has exactly the same law can the gravitational law be strictly established, the gravitational acceleration can always be exactly the same, and the two balls can land at the same time. However, the reality is that the law of gravity is only an approximation. Generally speaking, the law of interaction between any two physical fields and golf courses does not strictly follow the law of gravity, and there will be some differences in the acceleration of gravity. Therefore, any two objects do not always fall from the same height at the same time.
According to the core and field theory of matter, the essence of gravity is electric field force, and the gravity between two objects only depends on the structure and size of the object field, and the size of gravity mainly depends on the number of electric fields carried by two objects, or on the sum of amphoteric charges of objects (we can call the sum of positive and negative charges in a neutral object the sum of amphoteric charges of objects). Generally speaking, the more electric field photons an object carries, the greater the sum of the electric charges of the object. The number of photons in the electric field largely reflects the sum of the electric quantity of an object. Gravity is not directly related to the mass of the object (mainly the mass of the bare core). Therefore, for two objects with the same mass (mainly the same number of bare nuclei) on the earth, the larger the object with amphoteric charge, the greater the gravity of the earth, and the smaller the object with amphoteric charge, the smaller the gravity of the earth. The acceleration of gravity obtained by two objects with the same mass and different structural properties on the earth is different.
Compared with neutral objects composed of bare nuclei of electric particles, a single free bare nucleus of electric particles, such as electrons or protons, has the greatest ability to obtain electric field and the largest amount of electricity under the same external field environment. For two neutral objects, when the number of bare nuclei of positive and negative particles in each neutral object is completely equal to that of the other object, that is, when the total mass of bare nuclei of the two objects is completely the same, the object with loose structure has greater ability to obtain electric field from the external space environment than the object with tight structure, so the ratio of the total charge (sum of amphoteric charges) of this object to its own mass (which can be called the charge-mass ratio of neutral objects) is also large. Then when it interacts with another object, such as the earth (electric field), it is also affected by the gravity of the earth, and the acceleration is also large. It is inferred that for two objects with the same mass, the object with loose structure and low density will be subjected to greater gravity acceleration than the object with tight structure and high density, and will reach the ground first.
Due to the difference of material structure, such as the different constituent elements, the nuclei of light elements have stronger charging ability than the elements in the periodic table. The nuclei of light elements with specific gravity per unit mass have more electric field photons and have a strong ability to attract electrons outside the nucleus. The whole atom also absorbs more electric field photons from the surrounding space, so light element substances and heavy element substances have different gravitational characteristics in the same gravitational field, such as the ground field. Different gravitational accelerations g=F/m are generated, and the gravitational acceleration generated by a light element substance or element nucleus when it falls freely in the same gravitational field is greater than that of a light element substance or element nucleus, and the light element substance or element nucleus falls to the ground first.
Whether two balls land at the same time and the principle of equivalence must be analyzed from the microstructure and interaction of matter. If we can do the experiment of electrons and protons falling freely, there will be no simultaneous falling. Theoretically, it can be known that the gravity of electrons is equal to that of protons, but the mass of electrons is smaller than that of protons, so it can be predicted that electrons will gain greater acceleration than protons and reach the ground first.
The key conditions for redoing the free fall experiment are: different structural densities, long distance between vacuum and falling body, and strict control of conditions to ensure the accuracy of the experiment.