How to calculate the closing force

1.

Finally, the task of exerting force is to apply the whole body force to the javelin in the shortest time through the throwing arm and hand action on the basis of the stable support of both feet, so as to achieve a greater release speed. Therefore, whether the javelin can complete the displacement from the position at the end of run-up to the release point in the shortest time under a certain working distance, It depends on the strength of the muscles

According to the principle of momentum: ft = m (v. -) 5) = m △ V

in the above formula: v. V is the speed at the end of the run-up, f is the force exerted by the throwing arm on the javelin, and T-F is the action time

Compared with javelin,

△ V is the speed change of javelin, and for human body, it is the speed of completing throwing action. When the range of motion is fixed, that is, t is relatively fixed, f is proportional to △ v. Therefore, muscle contraction is the key factor to determine the degree of action

It can also be seen from the formula that when f is fixed, t is proportional to △ V, but the increase of t can only be obtained by depending on the extension of working distance, not by artificial subjective extension. On the contrary, people should try their best to shorten the action time subjectively in order to obtain good throwing effect. On this point, we can draw the following conclusion: assuming that the speed of the gun before the final force is V, The release speed is v., Since the motion in the process of gun throwing can be approximately regarded as uniform acceleration motion, it is concluded that:

ft = MV

s = 12at2

V = at

when the working distance s is fixed, shortening the action time t will have a positive effect on the increase of the force F of the human body on the gun. Similarly, when the force is fixed, the increase of the working distance s will also help to improve the force F. Therefore, improving the contractility of the related active muscles and their cooperative muscles is concive to improving the Javelin Athletes' movement speed

2. bitcoin mining is a process of using computer hardware to do mathematical calculation for bitcoin network to confirm transactions and improve security. As a reward for their service, miners can get the Commission included in the transaction they confirm, as well as the newly created bitcoin. Mining is a professional and competitive market. The bonus is divided according to the amount of calculation

the mining method of ant miner is the same as that of Avalon miner, but at present, you need to join a mining pool for mining. If you use your 180g miner to dig ore alone, it is difficult to dig bitcoin.

3. The concept of the Internet of things has been put forward for many years. In recent years, with the popularity of big data and artificial intelligence, the Internet of things seems to fade out of people's vision. However, as a relatively mature technology, the Internet of things has been deeply implemented in instry. Many domestic instrial companies have launched IOT concept network in a shares and US shares. What are the instrial IOT concept stocks in 2018? Let's take a look at it today
PTC (NASDAQ: PTC) recently announced the publication of a series of research reports on the status of instrial innovation, which are published twice a year. Based on the data of PTC customer base, this series of reports provides objective analysis of the current development status and future promotion plans of instrial Internet of things (IOT) and augmented reality (AR) technology. Each report examines the instries that drive the popularity of these two technologies, the functions and use cases deployed across the blockchain, and the types of business value they bring
Mike Campbell, executive vice president of thingworx platform of PTC, said: "with the continuous maturity of the technology and business model of instrial Internet of things and AR, its popularity will show a rising trend. PTC combines market experience and massive penetration data to truly examine these rapidly evolving markets from a comprehensive perspective. "
as described in the "status quo of instrial Internet of things" and "status quo of instrial augmented reality", instrial Internet of things and Ar are no longer just promising emerging technologies. In 2018, investing in such technologies has become a key strategy for many organizations, especially for technology stocks that involve complex manufacturing and operational processes. Among the PTC customers who have adopted the instrial Internet of things or AR technology, 83% and 85% of the instrial Internet of things users and AR users have migrated to the full-scale proction environment or plan to complete the migration in the next 12 months, respectively< The main points of the report are as follows:
current situation of instrial Internet of things
1. At present, the instrial Internet of things is mainly used by large proct manufacturers in instrial procts (25%), electronics and high technology (22%), automobile (13%) and aerospace and national defense (11%)
2. The economic potential of instrial Internet of things has attracted the attention of the international community, and has spawned some global initiatives aimed at promoting the development of global instrial Internet of things< At present, most of the solutions are used in manufacturing and operation (48%), and the collected data can be used to improve the process, forecast the maintenance demand and improve the overall operation efficiency
Instrial Internet of things is no longer an emerging technology - it has developed into a mature and widely recognized stage. The instrial Internet of things is now being deployed in large quantities, involving a wide range of functions from proct development to manufacturing and services
current situation of instrial augmented reality
instries such as instrial procts (21%), automobile (11%), aerospace and national defense (8%) are leading the initial popularization of AR
AR is widely used in all aspects of the value chain, especially in service (19%) and manufacturing (18%)
AR can become a powerful tool for operation tips and guidance, thus providing an entry point for many organizations, especially those instries involving hundreds of key processes, such as real-time monitoring and improving equipment overall efficiency (OEE)
large scale investment in underlying hardware and software technology will promote ar penetration to a critical point, so that pilot projects can quickly migrate to the full proction environment< Relevant concept stocks:
000701 Xiamen Xinda: the first batch of partners of Alibaba IOT platform
300203 focus technology: the company signed a strategic cooperation framework agreement with the people's Government of Zhangqiu City, Shandong Province, to build "smart environment cloud data center", "smart environment decision-making and public service platform", "smart environment emergency command and scheling platform" and "atmospheric haze pollution monitoring and warning platform"
300007 Hanwei Technology: the leader of domestic gas sensors, mass proction of flow and pressure sensors, establishment of municipal gas IOT network subsidiary; 51% equity of Shenzhen Mingzi IOT Technology Co., Ltd
000851 Gaohong: at present, Datang Gaohong has clearly focused on the development of RFID Business in logistics application and value-added application of the combination of RFID and TD
002881 megger Intelligence: main business: wireless sensor network system solutions, MEMS sensor chips< Haitong news: the company is the largest supplier of communication network physical connection equipment in China
300590 move to communication: the company brings together technical experts and business elites in the field of wireless communication technology, and is a leading provider of wireless Internet of things devices and solutions in the instry
300259 Xintian Technology: xiongan + Alibaba Internet of things, al concept
300205 Tianyu Information: a leading provider of procts and solutions in the field of data security in China
300286 ankerui: the main manufacturer of intelligent power monitoring system and instrument for domestic instrial and mining enterprises
600271 Aerospace Information: committed to the research and development of IOT chip
002474 Rongji software: signed a memoranm of cooperation with Huawei and Fuzhou municipal government to jointly promote the construction of the first NB IOT Experimental Bureau in China
300131 Yingtang Zhikong: Fengtang IOT, the holding subsidiary of the company, and Tencent technology signed a cooperation framework agreement on procts and services of Internet of things
000997 New World: Taking the Internet of things as the main line, the company realizes "one main" (core technology of Internet of things perception and identification, key procts of Internet of things) "two wings" (Internet of things application and Internet of things business model innovation)
000682 Dongfang Electronics: Dongfang Electronics Group has a strong RFID instry in the core area of the Internet of things, with an authentic "Internet of things" concept
002047 BAOYING shares: it plans to increase the capital of Shenzhen guochuang Zhilian Network System Co., Ltd. with 100 million yuan in cash to obtain 20% equity. Guochuang Zhilian has LTE wireless smart city solution, wireless broadband private network system and terminal equipment, and provides solutions for government affairs and police private network, instrial Internet of things and smart city construction
002161 yuanwanggu: the company has invested in five Internet of things projects such as intelligent tracking device of railway train number
002093 Guomai Technology: the company has its own cloud platform, mass storage and big data solutions with independent intellectual property rights, and is deeply involved in the big data cloud computing of the Internet of things
300638 guanghetong: focus on the wireless communication field of Internet of things and mobile Internet, independently design and develop fibocom brand procts
300183 Neusoft carrier: chip level equipment manufacturing, benefiting from the chip demand brought by the development of Internet of things
300310 Yitong century: cooperate with Jasper, the world's best Internet of things platform, to provide Telecom grade Internet of things connection
000063 ZTE: NB IOT chip design leader 4G, 5g<
300066 Sanchuan wisdom: a leading enterprise in smart water instry in China, and at the same time marching into the big data field of Internet of things
002017 Dongxin Heping: its business scope is involved in many smart card application fields such as identity recognition and RFID (electronic tag)
300259 Xintian Technology: the company has researched and reserved nb-iot technology in the early stage, and its procts use narrowband Internet of things technology<
600100 Tongfang Co., Ltd.: the company is a supplier and system integrator of smart card and RF technology procts. Its procts involve the design and supply of IC chips such as ID, telecom, financial payment, information security, etc
002711 oupu: the company's "ground network", "Sky Network" and "Golden Network" three networks in one strategic layout
300275 mayanson: the security monitoring technology of Internet of things is leading in the instry. With the "security application of Internet of things instry", it actively arranges many emerging businesses with huge development space, such as urban pipe network and gas safety, environmental protection emergency, public security fire protection, structural safety, safety cloud service, etc
300456 Neville Technology: acquired celex MEMS foundry (the world's largest), raised 750 million yuan to build an 8-inch MEMS proction line in Beijing<
300458 Quan Technology: the design manufacturer of intelligent application processor SOC and intelligent analog chip
300098 Gao Xinxing: Guangzhou Zhixing IOT, the holding subsidiary, mainly provides IOT solutions for operators from the development of IOT related business platforms and procts, and participates in the operation and security of operators' IOT business cooperation
300101 core technology: MEMS Integrated Navigation: MEMS gyroscope and accelerometer
000727 East China Technology: East China technology is one of the core sensor manufacturers in the Internet of things instry
the above is the details of instrial IOT concept stocks in 2018. It can be seen that there are still many companies involved in IOT, and IOT will become a common technology in proction. If you still have more to say, you might as well take a look at the stock market knowledge with Xiaobian. More information is available on weishang times
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4. 1. Force (f): force is the action of an object on an object
the forces between objects are always mutual
unit of force: Newton (n)
force measuring instrument: dynamometer; The laboratory uses a spring dynamometer
the effect of force: make the object deform or change the motion state of the object
the change of object motion state refers to the change of object velocity or motion direction
2. The three elements of force: the size, direction and action point of force are called the three elements of force
the diagram of force should be scaled; A schematic diagram of the force without scale
3. Gravity g: the force exerted on an object e to the attraction of the earth. Direction: vertical down
relationship between gravity and mass: g = mg, M = g / g
G = 9.8 N / kg. Pronunciation: 9.8n/kg, which means that the gravity of an object with a mass of 1kg on earth is 9.8N< Center of gravity: the point where gravity acts is called the center of gravity of an object. The center of gravity of regular object is on the geometric center of the object, and the center of irregular object may or may not be on the object
4. Equilibrium condition of two forces: acting on the same object; The two forces are equal in magnitude and opposite in direction; Acting on a straight line
under the balance of two forces, an object can be stationary or move in a straight line at a constant speed
the equilibrium state of an object means that the object is in a state of static or uniform linear motion. The resultant force of the external force on an object in equilibrium is zero
5. The combination of two forces on the same line: the direction is the same: the resultant force F = F1 + F2; The direction of resultant force is the same as that of F1 and F2
the direction is opposite: the resultant force F = F1-F2, and the resultant force direction is the same as that of the large force
6. Under the same conditions, rolling friction is much smaller than sliding friction
the sliding friction is related to the normal pressure, material properties and roughness of the contact surface Newton's first law is also known as the law of inertia, whose content is that all objects always keep static or uniform linear motion when they are not affected by external forces
inertia: an object has the property of keeping the original static or uniform linear motion state, which is called inertia.

5. Win win points have the basic characteristics of the Ponzi scheme. It's not easy to judge whether it's illegal, but it's better not to touch it. It's very risky. Now the fraud in the virtual currency circle is very rampant and can not be stopped repeatedly. On the one hand, the government's crackdown is not enough; on the other hand, there is a lack of relevant laws
is it a reliable digital currency? Compare it with bitcoin, Ruitai, Laite and other mainstream cryptocurrencies.

6. The emergence of DCEP is bound to have an impact on the whole currency circle in China
it has nothing to do with me
just mine

7. 1. The understanding of chess form. This is probably one of the most important parts. What is a good form, what is a bad form, where is the key point, the understanding of this aspect is often an important distinction between high and low hand. Therefore, to see how a person's chess power is, we can generally judge by his chess shape
2. Calculation is an important part of playing chess, and is the basis of middle game and officials. How to calculate the path determines the strength of chess. The classic of chess says, "if you win more than you win, if you don't win less, it's not enough."
3. Overall view. Whether there is overall planning in playing chess, the direction of playing chess, the use of hands, etc. probably belong to the category of overall situation. In my personal experience, in a match of equal strength, as long as it is not a very urgent fight, the overall situation will often affect the balance of victory and defeat
4. This part of the content should be slightly repeated with the understanding of chess type, but not exactly the same. The understanding of chess type is often "normal form", while the use of sub effect is at a higher level. The level of sub effect is also an important measure to evaluate the level of chess power
5. Situation judgment. Amateur players may not think it's important. But the more I play chess, the more important it is to judge the situation. Situation judgment is not only a point, but also a "choice". I remember Lin Haifeng once said that the most difficult part of go is "selection and judgment". In fact, we all know a lot of moves. The key lies in our own understanding, which one is the best. Maybe this part of the content is deeper for professional chess players
all of the above five parts are indispensable in chess power. How to quantify them? In terms of amateurs, is the following division appropriate
understanding of chess form accounts for 30%
calculating way accounts for 25%
overall situation view accounts for 20%
sub effect accounts for 10%
situation judgment accounts for 15%

8. Yes, the pages inside and outside the tube are poor

9. Calculate the stress area (using the method of ring area), and then look at the maximum pressure that aluminum can bear