Btbbtc and CTC

1. C2C is the business model of Taobao and eBay. B2C is the business to customer, which refers to the business between business and customers. Typical examples are tmall and Jingdong. B2B is the business to business, which refers to the business between enterprises. Typical examples are Ali, b2o, o2o and so on. Most of them are abbreviations of some business models!!

2. Unknown_Error

3. The simplest way is to take your computer host and monitor to the computer store for repair. If you want to check by yourself, you need to prepare a monitor to replace the original one to see if there is an image. If there is an image, the monitor is broken. If there is no image, the graphics card is faulty.

5. 1. Check whether the keyboard light is on, and press the NumLock or uppercase switch key on the top left of the keypad to see if the keyboard indicator light reacts. If so, pay attention to the sound of the system starting. If the keyboard light responds, the system starts normally, but it does not display
generally, the display cable is not plugged in or loose. Check whether the display cable behind the monitor and the chassis is loose. If there is an independent graphics card, see if it is inserted into the mouth of the set display
2. If the keyboard light does not respond, it is not a line problem. This kind of situation is usually caused by poor memory contact. Unplug the power and remove the screws on the left side of the chassis. Remove the left panel. Two or four or six slots can be seen next to the fan on the motherboard (usually on the top or right). There is a bar like memory mole of little overlord game card on it. There are plastic buttons on both sides of the slot. Press the button on both sides and the memory will pop out. Take out the memory, wipe the golden contact point with rubber or paper, and then insert it back. Pay attention to the direction. There is a groove in the memory mole. (press the top of the memory with your thumb and press it down evenly. The clasps on both sides will snap up and make a click sound). Power on test. If it still doesn't work or you hear a long alarm, it means that the memory is not installed properly. Try inserting it again or another slot
if it is a stand-alone graphics card (inserted in the long slot under the fan, there is a buckle at the tail, which is usually fixed with screws), it can also be removed and wiped
3. If you can't boot up after repeatedly plugging in and out the memory, there may be a problem with the graphics card or memory. Independent graphics card can be inserted set show try. Jixian can't do it. It's suggested to find a professional to deal with it. May be the motherboard or CPU, power problems. It is not recommended to deal with it by oneself.

6. It's not f = ma. This formula is Newton's second law, which says that force proces acceleration
the problems of impact and collision should be momentum theorem or impulse formula, etc
impulse I = p2-p1 = mv2-mv1 = f t
to judge whether the generated force is the same, we also need to know the final velocity V2 and impact time t.

7. First of all, we should know:
(1) the small iron ball is completely immersed at the beginning
(2) it is not stated whether the small iron ball is solid or not
(3) it sinks after the line is cut
(1)
now analysis: water provides buoyancy for the iron ball, because the volume of the small iron ball is constant, so the water discharged is also constant, so the buoyancy of the iron ball is constant, The gravity it receives is greater than the buoyancy, which is determined by iron.
(2)
continue to analyze: in the process of the sinking of the cutting line, what force does the iron ball receive besides the buoyancy of water, because the gravity of the iron ball & gt; Buoyancy, so we have to move downward, but in the process of movement, we must be subject to the resistance of water. Just think about it, just like swimming, we will be subject to the resistance of water when we swim forward. If you don't paddle backward, you will stop slowly. But now it's downward. We can understand that the faster the speed is, the greater the resistance is. The faster we want to swim forward, the stronger the resistance is, indicating that the resistance is increasing. So as long as the iron ball gravity & gt; If the iron ball is subjected to buoyancy + resistance, then the speed of the iron ball still needs to accelerate, and the buoyancy will continue to increase until the buoyancy of the iron ball increases to = gravity of the iron ball - buoyancy of the iron ball, then the speed will not change, and the force will be balanced at this time. Because water provides an upward resistance, it is subject to a downward force. This force, together with the gravity of the cup and water, acts on the bottom of the cup (directly or indirectly), which is displayed as the indicator of the platform scale
then we can make a conclusion about the change of the scale indication:
(1) the speed of the ball keeps increasing until the ball touches the bottom of the cup, so the scale indication keeps increasing
(2) the speed of the ball increases, and the speed of the second half is constant, so the scale indication first increases and then remains unchanged

summary: it depends on the distance between the ball in the cup and the bottom of the cup. Generally, the resistance of water will not change, or will not change much. According to the different water temperature, the density of water is not the same, the buoyancy is not the same, and the resistance is not the same.

8. Correct answer: I = ft = 10 * 2 = 20ns;

9. How to learn physics well for senior high school students
1. Among all the subjects of Science in senior high school, physics is relatively difficult to learn. Most of the students who have studied physics in senior high school, especially the students with poor physics scores, always have such questions: "if you understand in class, you will not be able to do questions after class." This is a common problem, which is worthy of serious study by physics teachers and students. The following high school physics learning methods, talk about some of their own views, in order to help students learn
2. First of all, analyze the common question raised by the students above, that is, why do you understand in class but not do it after class? As a science teacher, I have such a personal feeling: for example, when I read a certain literary work, the description of natural scenery and the description of people's inner activities are all amazing, and I know it is so, but if I write with my pen, I may not be able to write other people's level. There is absolutely no problem in listening to other people's words, reading other people's articles, and understanding them, but it is not so easy to write them and turn them into your own things. For example, if a child wants to write something that he can say, he must go through repeated writing practice to reach that step. Therefore, if we want to change from understanding to being able to do, we need to practice more on the basis of understanding, so that we can master the rules and secrets, and really become our own things. This is also the place where we should work hard to learn high school physics. How to work hard, what specific requirements should be achieved in the learning process, and what problems should be paid attention to, let's analyze them in several levels
1. Memory: in the study of physics in senior high school, we should memorize the basic concepts, rules and some of the most basic conclusions, that is, the most basic knowledge we often mention. Students often ignore the memory of these basic concepts and think that they don't have to memorize these literal things in learning physics. As a result, few students can accurately say the physics concepts in the review of senior three, even in the cram school. I can't say absolutely that the incomplete recitation of physics concepts has a great impact on your study in a certain examination or stage. But it can definitely have an internal adverse effect on your understanding of physics problems and the formation of your whole physics system knowledge. It can't be said that any question in any examination will lose points because of your incorrect concepts. Therefore, learning Chinese requires memorizing famous sayings and aphorisms, learning mathematics requires memorizing basic formulas, and learning physics also requires memorizing basic concepts and laws. This is the first condition for learning physics well and the most basic requirement for learning physics well. Without this step, the following study is impossible
2. Accumulation: it is the work after memory in the process of learning physics. On the basis of memory, we constantly collect a lot of information about physics knowledge from textbooks and reference materials. Some of the information comes from a question, some from an illustration of a question, and some from a short reading material. In the process of collecting and sorting out, we should be good at analyzing and classifying different knowledge points. In the process of sorting out, we should find out the similarities and differences, so as to remember them. The process of accumulation is a process of struggle between memory and forgetting. However, it is necessary to make knowledge more comprehensive and systematic through repeated memory, and to make formulas, theorems and laws more closely linked. Only in this way can we achieve the purpose of accumulation. We must not repeat our work like a bear breaking a stick and mechanically memorize without thinking. As a result, we can only remember more than we forget
3. Synthesis: physics knowledge is divided into chapters and sections, and the contents required by Physics Syllabus are also one by one. They are not only related to each other, but also different from each other. Therefore, in the process of physics learning, small synthesis should be carried out continuously, and then systematic synthesis should be carried out after learning the knowledge of grade three in senior high school. In this process, students are required to have a higher ability. The contents of the chapters are related to each other. Different chapters can be compared with each other, and the knowledge before and after can be really integrated into one. In this way, we can graally find the connection of knowledge from the synthesis, and also find the interest in learning physics knowledge
4. Improvement: with the memory and accumulation of the previous knowledge, we can improve our problem-solving ability. The so-called ability improvement is to improve the ability to solve and analyze problems. For a topic, we should first see what the problem is - mechanics, heat, electromagnetism, optics or atomic physics. Then we should clarify the research object, combine with the conditions given in the topic, apply the relevant physical concepts and laws, and also use some physical first-class and second-class conclusions, To get the result smoothly. It can be imagined that if the basic concepts of physics are not clear, the conditions given or implied in the questions can not be seen, or the formulas used to solve the problems are not right, or the primary or secondary conclusions should be used, but the original formulas are used, the speed and correctness of solving the problems will be affected, and it will become empty talk to get high scores in the examination. The first thing to improve is to be proficient in solving problems, then to be flexible in solving problems, and then to be innovative in solving problems. This includes multiple solutions to the same problem, from which the simplest method can be selected; It also includes a solution to multiple problems, a method to successfully solve multiple similar problems. It can be used skillfully and easily
to sum up, there are six levels in learning physics, that is, first understand, then remember, practice and use, graally become proficient, practice makes perfect, innovate, and finally reach the highest level of learning physics from the initial goal of basic knowledge
in the process of physics learning, according to the cognitive process from simple to complex, comparing the six levels of learning, graally find their own position and level, find out their own shortcomings, and then determine their own direction of improvement and efforts
learning in high school is to prepare for university learning, which puts forward higher requirements for students' self-learning ability. The above-mentioned basic process of physics learning memory, accumulation, synthesis and improvement is the cultivation process of their self-learning ability, learning learning methods and being interested in physics, After mastering the characteristics of the close combination of physics with practice, I will surely do well in physics in senior high school
2 how to learn physics well
physics is a natural science course, which is relatively difficult to learn. You can't learn it by rote. If you memorize it word for word, you still can't work out a topic. Physics class junior high school, high school, University once again, junior high school qualitative things, high school quantitative things, University quantitative things more, and to use advanced mathematics to calculate. So, how to learn physics well
if you want to learn physics well, you should be able to learn not only physics well, but also other courses such as mathematics, chemistry, Chinese and history well, that is to say, you can learn what you learn. In fact, in school, the students we see who are good at learning all subjects well, and the students who are poor in learning all subjects poorly. Basically, apart from the congenital factor of very small probability, there is a problem of learning methods
who doesn't want to be a good student, but if you want to be a really good student, the first thing is to study hard, that is, to dare to bear hardships, to cherish time, and to persevere in learning. Establish confidence, firmly believe that they can learn any course, firmly believe that "the law of energy conversion and conservation", firmly believe that there are several efforts, there should be several gains. For this, please look at the following three quotations:
I never believe that any innate or acquired talent can succeed without a firm quality of long-term hard work
- Dickens (British writer)
the main reason why some people can surpass others is not so much genius as his indomitable spirit of persisting in learning and never giving up if he fails to achieve his goal
- Dalton (British chemist)
time is the fastest and slowest, the longest and the shortest, the most ordinary and the most precious, the most easily neglected and the most regretful thing in the world
- Gorky (Soviet writer)
the first point mentioned above should be the attitude towards learning and the way of thinking. The second is to understand that as a student, there are the following eight links in learning: making plans → preview before class → concentrate on class → review in time → work independently → solve problems → summarize systematically → extracurricular learning. Here the most important is: concentrate on class → timely review → independent work → solve problems → system summary, these five links. In the above eight links, there are many learning methods, the following is for the characteristics of physics, for "how to learn physics", this problem puts forward some specific learning methods
(1) three basic principles. The basic concepts should be clear, the basic rules should be familiar with, and the basic methods should be proficient. As for the basic concept, take an example. Like speed. It has two meanings: one is the speed of the size; The other is the ratio of distance to time (for example, in uniform circular motion), and the speed is the ratio of displacement to time (for example, in uniform linear motion). As for the basic law, for example, there are two formulas for calculating the average velocity, v = s / T and V = (VO + VT) / 2. The former is a definition, which is applicable to any situation, while the latter is a derivation, which is only applicable to the situation of uniform speed change linear motion. Let's talk about the basic methods. For example, the holistic method and the isolation method are often used in the study of middle school problems, which are typical complementary methods. Finally, let's talk about another problem, which is beyond the three basic problems. It is in the process of learning physics that we sum up some concise and easy to remember practical inferences or conclusions, which are very useful to help solve problems and learn physics well. For example, "the potential decreases along the direction of the electric field line"“ The tension on the same rope is equal "“ When the acceleration is zero, the velocity is maximum“ Lorentz force does not work, etc
(2) work independently. To be independent (refers to do not rely on others), quality and quantity to do some problems. There should be a certain number of topics, not too few, but also a certain quality, that is to say, there should be a certain degree of difficulty. No one can learn mathematics and chemistry well without going through this pass. To solve problems independently, sometimes it may be slower, sometimes it may take a detour, sometimes it may not even work out, but these are normal and the only way for any beginner to succeed< (3) physical process. If we want to be clear about the physical process, there must be hidden trouble in solving the problem if we can't make it clear. No matter how difficult the problem is, we should try our best to draw a picture. Some of them need to draw a sketch, others need to draw an accurate picture, and we need to use compasses, triangular plates, protractors, etc. to show the geometric relationship. Drawing can change abstract thinking into image thinking, and grasp the physical process more accurately. With graphs, state analysis and dynamic analysis can be made. State analysis is fixed, dead and discontinuous, while dynamic analysis is live and continuous< (4) class. Listen carefully in class, don't think or think as little as possible. Don't be self righteous, learn from the teacher with an open mind. Don't think that the teacher is simple and give up listening. If this happens, it can be regarded as review and review

10. It should be the same principle as controlling multiple computers. I know two ways to control multiple computers. One is remote monitoring computer desktop. For example, in an enterprise, when some bosses want to supervise the desktop of employees, they will download and install some remote control software to bind the hosts of employees to their own computers, and then they can call up the computers of employees to see their desktop at any time; The other is to rent someone else's computer, get the other party's computer information, you can remote control. I think what you said is very similar to the first way above, that is, if you don't know whether you can control so many mobile phones. Now on the market, there are software that can remotely control mobile phones, such as sunflower remote control software. You can try it yourself, but it costs money
good intentions... I...