1, from the physical point of view, the force will be generated after the object falls for a certain period of time, and its formula is G=mg. M= mass, g= acceleration of gravity (9.8 meters per second). For example, an object with a mass of 100KG falls freely for 5 seconds, and the resultant force is 100*9.8*5 =4800KG. The empty weight of aircraft B737-800 is 4 1, 4 1.3kg, and the total weight is about 80000kg when it is filled with oil. It fell at an altitude of 8000 meters, and the force generated with the ground was nearly 10 million tons. So after the plane crashed, it smashed a pit several meters deep on the ground. As a plane passenger, you can't bear such a huge force.
2. From the physiological structure of human body, after the plane falls from a height of 8,000 meters, with the increase of the falling speed of the plane, the sense of weightlessness becomes stronger and stronger, and the pressure borne by the human body and the blood flow of the human body will flock to the brain, causing the passengers on the plane to completely lose consciousness in mid-air, and even leading to the disappearance of life.
Judging from the explosion after the crash and landing of China Eastern Airlines, there will be few survivors. Aviation fuel is the most flammable fuel. In case of combustion and explosion, the high temperature and high fever will be as high as 1000 degrees or even higher. Therefore, even if the seat belt is fastened in the complete cockpit of the plane, people will be unable to move because of fire when they are in a coma. At the same time, high temperature and high pressure will also cause human body gasification. The specific situation is still waiting for the national rescue experts to make a conclusion. Pray.