How to calculate impact force in drop weight test
Starting from the essence of black money,
the essence of black money is actually a special solution generated by a bunch of complex algorithms. A special solution is one of the infinite (in fact, bitcoin is finite) solutions that can be obtained from the equations. Every particular solution can solve the equation and is unique[ 8] In the metaphor of RMB, black money is the serial number of RMB. If you know the serial number of a note, you have the note. The process of mining is to constantly seek the special solution of the equation system through huge amount of calculation. The equation system is designed to have only 22 million special solutions, so the upper limit of bitcoin is 22 million[ 8]
to mine the dark coin, you can download the special dark coin calculation tool, register various cooperative mine pool websites, fill the registered user name and password (miner user) into the calculation program, and then click the operation to officially start. After completing the installation of the darkcoin client, you can directly obtain a darkcoin address. When others pay, you only need to post the address to others, and you can pay through the same client. After installing the Black Coin client, it will distribute a private key and a public key. You need to back up your wallet data containing your private key to ensure that your property is not lost. Unfortunately, if the hard disk is completely formatted, the personal dark coin will be completely lost
RMB can also be electronic and more flexible than paper money. The central bank's digital currency is the electronic RMB, which is equivalent to paper money, but more flexible than paper money. It can also track your capital flow, and can pay without network
Calculation formula: ft = {MV
F is the average force, t is the time, M is the mass of the object, V is the velocity, and} is the variation; This formula is understood as that the impact force and its time acting on the object are equal to the change of momentum of the object
F Δ t=m Δ V is a vector. When applying the momentum theorem, we should follow the parallelogram table rule of vector operation, or we can use the orthogonal decomposition method to transform vector operation into scalar operation. Suppose that FX (or FY) is used to represent the component of the combined force on the X (or y) axis Or) and VX (or vy) represent the components of the initial velocity and final velocity of the object on the X (or y) axis, then
IX = mvx-mvx & # 8320
Iy=mvy－mvy₀
The above two formulas show that the component of the impulse of the combined force on a certain coordinate axis is equal to the component of the increment of the momentum of the object on the same coordinate axis. When we write the component equation of the momentum theorem, for the known quantity, the positive value is taken for those in the same direction as the positive direction of the coordinate axis, and the negative value is taken for those in the opposite directionfor unknown variables, it is generally assumed that the direction is positive, if the calculation result is positive. It indicates that the actual direction is consistent with the positive direction of the coordinate axis. If the calculation result is negative, it indicates that the actual direction is opposite to the positive direction of the coordinate axis
extended data
when two objects collide with each other, the momentum of one object increases and that of the other decreases. In volleyball spiking, the quality of the ball is constant. If the object [hand] used to collide is to make volleyball move fast, the quality is to be large. It requires not only the hand to participate, but also the arm and trunk to participate, and the hand, arm and trunk to coordinate to form an overall force to increase the hitting quality. In this way, the hitting time is very short, but the impact is very strong
the force that occurs when objects collide with each other. In the process of collision or strike, the force between objects first increases suddenly and then disappears rapidly, also known as impulse or collision force. The characteristic of the impact force is that the action time is very short, but the magnitude can be very large
in sports activities, such as baseball batting, table tennis batting, volleyball spiking, football kicking, etc., all belong to collision, and running and pedaling can also be regarded as foot and ground collision. Because the collision interaction time is very short, often only a few hundredths of a second or even a thousandth of a second, the momentum changes greatly in this very short time, so it is subject to a great impact force
first, the free falling time of 100 mm height:
t = (2 h / g) ^ 1 / 2
Second, the free falling speed of 100 mm height:
V = GT
third, the maximum bearing capacity of the test object at the moment = the weight of the weight of the code 25 kg * the free falling speed of 100 mm height / the impact time of the test object
The moon is the closest celestial body to the earth, and it is also the only one with human footprints except the earth. Human research on the moon can be traced back to ancient times, when there were records and predictions of lunar eclipses. Through the long-term research of ancient, modern and modern scientists, especially in the 40 years since the end of the 20th century, human beings have repeatedly landed on the moon, sampled and analyzed the lunar soil, and explored the moon with spacecraft. The results show that the moon has the basic conditions for human development and utilization
First of all, there are abundant material resources on the moon. There are all the elements and more than 60 kinds of minerals on the earth on the moon, and there are six kinds of minerals that the earth does not have. In the lunar soil, the content of oxygen is 40%, the content of silicon is 20%, and there are abundant calcium, aluminum, iron and so on There are three main types of rocks on the moon. The first is the lunar basalt rich in iron or titanium. The dark Yuehai basalts are mainly composed of clinopyroxene, basic plagioclase and ilmenite, and sometimes contain olivine and apatite, or microsatellite pyrite and metallic iron. More than 20 types of basalt have been found in the rocks retrieved from the moon landing. According to the content of titanium oxide, Yuehai basalt can be divided into high titanium, low titanium and very low titanium. These basalts are characterized by rich titanium and iron, no water bearing minerals, low oxygen fugacity, no trivalent iron, and various fine-grained to coarse-grained textures. The second is anorthosite, which is rich in potassium, rare earth and phosphorus. Plagioclase is composed of 95% plagioclase and a small amount of hypocalcite, mainly distributed in the lunar highland. The third one is made up of 0? The breccia composed of 1-1 mm debris particles is the proct of impact. Breccia can be divided into broken plagioclase, partial melting breccia, complex clastic breccia and deep metamorphic extrusive rock The lunar rocks contain all the elements in the earth's crust and about 60 kinds of minerals, of which 6 kinds are not found on the earth. Refractory elements account for about 65% of the mass of the moon. The resial liquid rich in iron and refractory elements condenses into a 250 km thick lunar shell. In lunar soil, oxygen accounts for 40%, which is the oxygen source of propellant and controlled ecological environment life support system; Silicon accounts for 20%, which is the raw material of solar array. The proportion of other elements is 6% ～ 8% for lead, 3% ～ 7% for magnesium and 5% ～ 11% for iron? 3%, CA 8% ～ 10? 3%, Ti 5% - 6%, Na, K, Mn in thousandth, Zr, Ba, SC, Nb in thousandth. Scientists heated lunar soil samples to 2000 degrees Celsius and found inert gases escaping from lunar soil, including helium, argon, neon, xenon and other radioactive particles. The moon is also rich in rare energy helium-3, which is an ideal fuel for nuclear fusion reactors. A thin film of rust free iron was also found on the lunar rocks. At first, scientists speculated that if this kind of iron was exposed to the earth's conditions, it would be immediately oxidized and rusted. However, according to the test results, this kind of iron would not be oxidized, which is commonly known as "pure iron". Pure iron is very useful to human beings. It is estimated that in developed countries, the annual loss e to metal corrosion accounts for about 1 / 10 of the national income. If pure iron can be proced on the moon and transported back to the earth for use, it will not only fill a gap, but also obtain great economic benefits, which is undoubtedly a great contribution to mankindit is very attractive to mine the natural mineral resources of the moon. Processing materials into final procts for space and ground use in the lunar base is expected to be a high-efficiency instry with a very attractive prospect
energy is one of the most serious problems for human survival and development. There are two ways to solve the energy shortage in the future: one is solar energy, the other is nuclear energy. The analysis of lunar samples and the discovery of helium-3 have injected new stimulants into lunar research and exploration, especially the attention of energy experts. However, the formation and distribution characteristics, storage capacity and application of lunar helium-3 are still problems to be solved in lunar scientific research. Only through a large number of explorations and field trips back to the moon can we get a satisfactory answer
the surface soil of the moon is composed of rock debris, powder, breccia and glass beads, with loose and rather soft structure. The soil in Yuehai district is generally 4-5 meters thick, while the soil in highland is thicker, but it is only about 10 meters. The particle size of lunar soil varies widely, ranging from a few centimeters to only one millimeter or tens of microns. These fine soils are generally called lunar st. Most of the lunar soil is composed of fine breccia and glass beads, accounting for about 70%, and small granular basalt and gabbro account for about 13%. The content of inert gas in lunar basalt and highland breccia is very low, and that in atmosphere is even lower, almost zero. However, the aerophilic elements in lunar soil and breccia are quite abundant. This is e to the injection of solar wind, which is actually a steady stream of particles ejected by the sun. In 1965, the chemical composition of the solar wind was directly determined by the "Venus 3" rocket. The results show that the solar wind particles are mainly composed of hydrogen ions, followed by helium ions. Due to the impact of foreign objects on the surface of the moon, the lunar soil materials are mixed, and these aerophilic elements exist in the depth of tens of meters. The depth of the exposed surface of the solar ion implanted object is usually less than 0? 2 microns. Therefore, the content of these elements is the highest in the most fine particles of lunar soil, and most of the particles injected with gas accumulate to form breccia or agglomerate in the interior of glass beads
The study of lunar rocks taken by Apollo 17 shows that the content of helium in lunar soil is (1-63) / 107, and the content of helium-3 is (0? 4～15／1010 It is estimated that 715000 tons of helium-3 can be supplied by the whole moon. Why people are interested in helium-3? Because helium-3 is the best choice for nuclear fusion fuel in the future. Helium is proced by fusion of deuterium and helium-3. This fusion reaction is safe, clean and easy to control. On the earth, the known helium-3 resources in natural gas deposits can only maintain the consumption of a 500 MW power plant for several months, while the electricity generated by helium-3 in the lunar soil is 40000 times of that of the United States in 1985. Considering the cost of exploitation, exhaust, isotope separation and transportation back to earth, the helium-3 energy reimbursement ratio is estimated to be 250. Compared with the proction of nuclear fuel by uranium-235 (the repayment ratio is about 20) and the mining of coal on earth (the repayment ratio is about 16), this repayment ratio is quite favorable. In addition, about 6300 tons of hydrogen, 70 tons of nitrogen and 1600 tons of carbon can be obtained by extracting 1 ton of helium-3 from lunar soil. These by-procts are also necessary to maintain a permanent base on the moonin addition, a nuclear energy base can be established on the moon to transmit electric energy to a relay satellite in geostationary orbit, then to a receiving station on the earth, and then to various regions for users' use. It is not difficult to understand the far-reaching significance of returning to the moon only through the development and utilization of lunar helium-3 resources
The method of extracting oxygen from lunar surface soil has been studied for a long time. They used the lunar sand retrieved by Apollo spacecraft to conct experiments. At a high temperature of 1000 degrees Celsius, they contacted ilmenite in the lunar sand with hydrogen to generate water, and then extracted oxygen from the water by electrolysis. Research shows that it takes about 70 tons of lunar topsoil to extract 1 ton of oxygen. Considering the special situation of proction on the moon, it is suggested that a set of small chemical treatment equipment should be equipped at the same time of the construction of the lunar base, which can proce about 100 kg of liquid oxygen every day by using solar energy as power. The specific process is to use lunar rocks to react with methane at high temperature to generate carbon monoxide and hydrogen. In the second reactor with lower temperature, carbon monoxide reacts with more hydrogen to form methane and water; The water is then condensed and electrolyzed into oxygen and hydrogen, which are stored for use, while the hydrogen is sent to the system for recycling. It is predicted that the lunar oxygen generation equipment was originally used to provide oxygen for astronauts on the moon, but they do not need much oxygen. A 12 person base only needs 350 kg of oxygen per month. A set of oxygen making equipment can proce a considerable amount of oxygen after continuous operation. Therefore, ring the construction of the lunar base, a permanent liquid oxygen reservoir should be built at the same time, so as to supply the spacecraft as low-temperature propellant fuelit is very significant that in the process of oxygen proction, the "slag" obtained after chemical treatment has become a superior by-proct. This is because it is rich in free silicon and metal oxides that can be smelted. As long as appropriate instrial methods are adopted, it can continue to smelt and proce the valuable metal titanium in instry. The titanium proction process proposed by scientists is to extract titanium oxide from slag by mechanical crushing and magnetic separation, and then hydrotreat it at 1273 ℃ to proce titanium oxide. The iron is replaced by sulfuric acid, and then mixed with carbon. Chlorine gas is introced at 700 ℃ to form titanium tetrachloride after chemical reaction. Then, it is heated at 2000 ℃ and magnesium is put in to dechlorinate, and finally molten titanium is obtained
The refining method ofaluminum is more novel. The aluminum on the lunar surface is composed of a complex structure called plagioclase. After repeated experiments and studies, scientists have put forward a new set of aluminum smelting technology. The specific method is as follows: the moon rock is crushed, heated and melted at 1700 ℃, and then cooled to 100% in water to make a multi-quality ball, which is then crushed and added with 100 ℃ sulfuric acid to leach aluminum. After the silicide was removed by centrifugal separation and filtration, it was pyrolyzed at 900 ℃ to obtain the mixture of alumina and sodium sulfate. Then, the sodium sulfate is washed away and dried, and then mixed with carbon for heating. At the same time, chlorine gas is added to react with it to proce aluminum chloride. After electrolysis, the final proct pure aluminum is obtained
the construction instry cannot do without glass, so it is particularly important to proce glass on the moon. The common glass is composed of 71% ～ 73% silica, 12% ～ 14% sodium sulfate and 12% ～ 14% calcium oxide. The lunar soil contains 40% - 50% of silicon oxide, which is the main material for making glass on the lunar surface. The refining method is relatively simple. A variety of trace additives are added to the lunar soil according to the needs. After dissolving some useless ingredients with sulfuric acid, the moon glass can be made by melting at 1500-1700 ℃ and then rolling and cooling
The most exciting thing is that the data from the US lunar explorer launched on January 6, 1998 shows that there are 1-10 billion tons of water ice at the two poles of the moon. Since the atmospheric pressure on the surface of the moon is less than one trillion times that of the earth, the temperature on the surface of the moon can reach 130-150 ℃ where the sun shines on the moon, which is easy to boil and evaporate for the liquid water of the moon whose boiling point is far below 100 ℃. Moreover, e to the moon's small mass and weak gravity, it is unable to restrain the water vapor, resulting in the escape of gaseous water on the moon However, the poles of the moon are very special. For example, the south pole of the moon has a 2, 500 kilometer diameter