That's the component of a force

1.

1. Gravity g = mg

(vertically downward, g = 9.8m/s2 ≈ 10m / S2, the action point is at the center of gravity, applicable to the earth surface)

2. Hooke's law f = KX

{along the recovery deformation direction, K: stiffness coefficient (n / M), X: deformation variable (m)}

3. Sliding friction force F = μ FN

{opposite to the relative motion direction of the object, μ： Friction coefficient, FN: positive pressure (n)}

{rrrrrrr}

extended data:

different classification of force

1. According to the nature of force, it can be divided into gravity, universal gravitation, elastic force, friction force, molecular force, electromagnetic force, nuclear force, etc Note that gravity is not equal to gravity under all conditions Gravity does not point to the center of the earth under all conditions. Gravity is a component of the earth's gravitational force on an object, and the other component is a centripetal force. Only on the equator does gravity point to the center of the earth.)

According to the effect of force, it can be divided into tension, tension, pressure, supporting force, power, resistance, centripetal force, restoring force, etc

According to the research object, it can be divided into external force and internal force

According to the action mode of force, it can be divided into non-contact force (such as gravitation, electromagnetic force, etc.) and contact force (such as elastic force, friction force, etc.)

There are four basic interactions (forces): gravitational interaction, electromagnetic interaction, strong interaction and weak interaction

nature of force:

materiality: force is the effect of an object (matter, mass) on an object (matter, mass). When an object is subjected to a force, another object must exert this effect on it. Force cannot exist independently without an object

interactivity (interaction): the interaction between any two objects is always mutual, and the object exerting the force must also be the object under the force. As long as one body exerts a force on another, the stressed body in turn will surely add a force to the exerted body Generating conditions: the force is equal in size (the resultant force is zero, in a state of non directional static motion) or not equal, in the opposite direction, acting on two different objects, and acting on the same straight line. It can be summarized as: foreign body, equivalent, reverse, collinear. A pair of interaction forces must proce and disappear at the same time.)

Vectoriality: force is a vector, which has both magnitude and direction

simultaneity: the force proced and disappeared at the same time

independence: the effect of one force does not affect the effect of another

includes three elements: the size, direction and action point of the force. The accurate expression of the three elements of force by a directed line segment is called the diagram of force. The size is represented by the length of a scaled line segment, the direction is represented by an arrow, the point of action is represented by an arrow or the tail of an arrow, and the straight line along which the direction of a force follows is called the line of action of a force. The diagram of the force is used for the calculation of the force. When the judgment power is large, we must pay attention to the scale of the line segment, because even if one line segment is longer than another line segment, but the scale of the long line segment is also longer, the force represented by the short line segment is not necessarily smaller than that represented by the long line segment

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3. Using the parallelogram rule, the resultant forces of two forces are calculated first, then the resultant forces of the third force and the resultant forces are calculated, and so on

4. (1)
graphical method:
①
parallelogram rule: as shown in Fig. 1-8. When drawing, the action points of resultant force and component force should be the same, the ray representing force should be solid line, and the rest lines should be dashed line.
F2 = 2n
F = 5.3n
1n
F = 5.3n
F2 = 2n
F1 = 4N
Fig. 1-8
F1 = 4N
Fig. 1-9
②
triangle rule: calculate two known forces F1, F1, F1 = 4N
F1 = 4N
F1 = 4N
F1 = 4N
F1 = 4N
F1 = 4N
F1 = 4N < The resultant force of F2 can be illustrated at the end of F1, and then a directed line segment can be made from the beginning of F1 to the end of F2. The directed line segment represents the magnitude and direction of the resultant force of F1 and F2. This is the triangle rule. The resultant force can be obtained by using the triangle rule, as shown in Figure 1-9.
(2)
calculation method:
① composition of forces on the same line: when several forces are on the same line, the, Finding their resultant force can be simplified as an algebraic operation. First, the positive direction is defined, and the force in the same direction is positive. On the contrary, it is negative. When the component forces are on the same straight line and in the same direction, they are directly added, that is, f-sum =
F1 + F2; When the component forces are on the same straight line and in opposite directions, the larger force is directly used to subtract the smaller force, and the direction of the resultant force is the same as that of the great force, that is, fhe = F1-F2.
② when the component forces are perpendicular to each other, the resultant force can be obtained by Pythagorean theorem, that is, F2 =
F12 + F22, tan θ= F2 / F1.
③ composition of forces in special cases: if the two components are forces of equal size, the parallelogram drawn is a diamond. If the angle between the two components is a special angle, the two diagonals of the diamond can be used to divide each other equally, which can be summarized as a solution right triangle.
(3)
the size range of resultant force
the resultant force of two known forces varies with the angle between the two forces θ When you change θ From 0o to 180o, f = F1-F2 & lt; F & lt<
F1-F2.
7.
decomposition of force
1.
decomposition of force is the inverse operation of the composition of force.
it also follows the parallelogram rule, that is, taking the known force as the diagonal of the parallelogram, and the two adjacent sides of the parallelogram are the two components of the known force.
2.
decomposition of force
attention should be paid to the actual situation when decomposing the force, A given force can be decomposed into countless components. A force can be decomposed uniquely in the following cases: ① when the directions of two forces are known; ② when the magnitude and direction of a component are known. There are two common decomposition methods:
(1)
according to the actual effect of the force: determine the direction of two forces according to the actual effect of the force, (2)
(2)
orthogonal decomposition method: decompose a known force in the plane rectangular coordinate system along the mutually perpendicular X and Y axes. This decomposition method is called orthogonal decomposition method. It is applicable to decompose a known force in two mutually perpendicular directions. As shown in Figure 1-10, decompose f along the X and Y axes into FX = fcos θ、 Fy=Fsin θ.
3.
equivalence of resultant force and component force
when discussing resultant force and component force, great attention should be paid to their equivalence. The essence of force synthesis is to replace the effect of several forces with the effect of one (resultant force) on the premise of ensuring the same effect; The decomposition of forces is to replace the action of a force (resultant force) with the action of several forces (components) on the premise of ensuring the same effect.
just because the relationship between resultant force and component force is equivalent substitution, they cannot exist at the same time, For example, in Figure 1-11, an object on a smooth inclined plane can't add another resultant force f-joint considering its gravity g and the supporting force n of the inclined plane. If f-joint is included, the effect of F and N can't be included.
n
f-joint
G
figure 1-11

5.

I don't know why there are so many black people. Yang is the same to us ordinary people whether we can come back or not, with a neutral attitude

but it seems that everyone's evaluation of Yang is not good

everyone's comments on Yang are as follows:

1. infidelity: Yang Zhenning resolutely chose to serve the United States in the Sino US war and confrontation years, and later joined the United States nationality, which is disloyalty to the country. You know, he spent a lot of money on school, National Southwest Associated University

3. 2. Unfilial: when Yang Zhenning became an American citizen, his father, an older generation of intellectuals, could not accept this. He issued a statement to sever his relationship with Yang Zhenning, and he did not forgive Yang Zhenning until he died. Yang Zhenning mentioned in the interview that this is his lifelong regret

   Injustice: for personal interests, he would not hesitate to turn against his collaborator Li Zheng
   Shameless: from the end of 2004 to the beginning of 2005, 82 year old Yang Zhenning and 28 year old Weng fan, a master's degree student in Translation Department of Guangdong University of foreign studies, married again. They violated the principles and customs and were suspected of incest. They were a shameless person

4. the above is for reference only. If it's true, it's really disgusting< br />

6.

1. B3b, namely Guangzhou bus B3b Road, referred to as B3b

2, refers to the B2B instry, is a business model, refers to the tourism instry buyers, sellers, build a win-win information resources food (resale) supplier as the main line of business model

the starting and ending station of Guangzhou bus B3b road is luochongwei terminus (zengcha Road) Shangshe, which is one of the six branch lines of Guangzhou BRT test line on February 10, 2010, one of the three branch lines of Guangzhou bus B3 Road, and the other two branch lines are Guangzhou bus b3a Road and Guangzhou bus B3c road

Guangzhou bus B3b is an air-conditioned bus, operated by Guangzhou No.2 bus company, with single ticketing system and no ticket selling. It is a one-way bus, and the route type is BRT

extended information:

Introction to the stop and start and end time of Guangzhou bus B3b Road:

the start and end time of Guangzhou bus B3b road is from 06:30 to 07:30 (morning rush hour)

one way station introction: one way luochongwei passenger station - Fuli Peninsula Garden - Xichang Electric City - Dongfeng West Road - Municipal Children's Palace - Guangyi - Zhongshan Memorial Hall (Municipal Federation of trade unions) - Zhenggu hospital - Dongfeng Hotel - Xianlie South Road - Guangdong University of technology - Zoo South Gate - Tianhe overpass - Sports Center (BRT) - Shipaiqiao (BRT) - Gangding (BRT) - Jinan Normal University (BRT) - Huajing new city (BRT) - Shangshe (BRT) - (23 stations)

7. Tsinghua
it seems that everyone's evaluation of Yang is not good< People's comments on Yang are as follows:
1. Infidelity: Yang Zhenning resolutely chose to serve the United States ring the Sino US war and confrontation, and later became an American citizen. This is infidelity to his country. You know, he spent a lot of money on school, National Southwest Associated University
2. Unfilial: when Yang Zhenning became an American citizen, his father, an older generation of intellectuals, could not accept this. He issued a statement to sever his relationship with Yang Zhenning, and he did not forgive Yang Zhenning until his death. Yang Zhenning mentioned in the interview that this is his lifelong regret
3. Injustice: for personal interests, he would not hesitate to turn against his collaborator Li Zheng
4. Shameless: from the end of 2004 to the beginning of 2005, Yang Zhenning, 82 years old, married Weng fan, 28 years old, a master's degree student in Translation Department of Guangdong University of foreign studies
the above is for reference only. If it's true, it's really disgusting.

8. No matter which bank's POS, the platform they use is provided by UnionPay. The machine itself can be set up. You can charge a single line of cards, or you can charge all of them. This can be set manually on the POS

9. The floorboards are cubed and calculated from the width and width of the floorboards.

10. Take bus No.59 (bus No.15) from Dongguan east bus station, then get off at the Telecom Bureau Station (Nancheng)
transfer to minibus line X11 (adjusted on February 13) (bus No.2) and get off at qingnianggong station. Take about 220 meters to the central square of the city