How to calculate the strength

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

2. Do you mainly calculate the resistance of the bearing? This force is hard to calculate

3. If a person wants to push an object, then the force F given to the object should be equal to or greater than the friction f between the object and the ground, that is, the steps should be like this! In order to make the object move, f = f (friction) and f (friction) = mg * u (U is the friction coefficient) can be solved by numerical method.

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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.

5. The moment is calculated by multiplying the force by the arm of force
the distance from the fulcrum of the lever to the straight line representing the force is called the arm of force. The arm of force is represented by a dotted line, which is not necessarily above the lever, and the moment is the force multiplied by the arm of force
levers can be divided into labor-saving lever, laborious lever and equal arm lever. Labor saving lever is labor saving, but it costs a lot of distance; Hard lever is hard, but it saves distance; And the equal arm lever, the two arms of force are equal, neither labor-saving nor laborious
I hope I can help you.

6.

The resolution of a force transforms a force into two or more equivalent components. The basis of decomposition is the parallelogram rule of force (see the axiom of statics). In general, this problem can have innumerable solutions. Only when sufficient conditions are attached, can the definite solution be obtained

The decomposition of a force is the inverse operation of the composition of forces, which also follows the parallelogram rule (triangle rule, rarely used): if a known force is regarded as the diagonal of a parallelogram, then the two adjacent sides of the parallelogram which are at the same point with the known force represent the two components of the known force. However, if there are no other restrictions, for the same diagonal, you can make countless different parallelograms

For this reason, when decomposing a force, the following two ways can be used:

① decomposing according to the actual effect of the force -- first determine the direction of the component force according to the actual effect of the force, and then calculate the size of the component force according to the parallelogram rule

(2) according to the "orthogonal decomposition method", the rectangular coordinate system is selected reasonably, and then the known force is projected onto the coordinate axis to obtain its two components

for the second decomposition method, we will focus on several typical problems of decomposing the force according to the actual effect: decomposing the oblique upward tension on the object placed on the horizontal plane, placing the object on the spring platform scale, paying attention to the indication of the spring platform scale, then applying a horizontal tension, and slowly deflecting the direction of the tension upward from the horizontal direction, The indication of the platform scale graally decreases, which indicates that the pulling force not only has the effect of pulling the object horizontally forward, but also has the effect of lifting the object vertically upward. Therefore, the oblique upward pulling force can be decomposed along the horizontal forward and vertical upward directions. As shown in the decomposition of gravity on the inclined plane, when a layer of sponge is laid on the inclined plane and a cylindrical weight is placed, it can be observed that when the weight rolls down, it can also make the sponge deform and have pressure effect, which explains why the gravity is decomposed into two components F1 and F2

7. A: three unknown quantities (two unknown forces at point a and one unknown force at point B) can list three equilibrium equations: the balance of x-axis force, Y-axis force and bending moment around point a
because point B has smooth contact, there is no friction and only the supporting force perpendicular to the wall. We can take the distance from point a and list an equation. There is only an unknown force at point B to solve the unknown quantity. After calculating an unknown force at point B, the balance of x-axis force and y-axis force can be listed as a whole, and then two unknown forces at point a can be obtained.

8. Positive dazzle theorem

9. There are two elements in doing work: 1. The force acting on the object; 2. The object moves a certain distance in the direction of the force.
If an object moves vertically and uniformly, then the work done on it is related to its weight. The specific relationship is: w = GH, W is the work, G is the weight of the object, and H is the distance of the object moving in the direction of the force