How to calculate the minimum 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

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

3. The maximum stress value of the target pair is the highest point (wave crest)
the minimum stress value is the lowest point (wave trough)
the average stress value is the middle line of the sine curve
the stress amplitude is the value from the middle line to the highest point or the lowest point

4. The minimum force is greater than the weight of the cuboid, so it's 6N

5. The maximum value is very simple. The direction of the three forces is the same. The maximum value of the resultant force is equal to the sum of the three forces. The minimum value depends on the specific size of the three forces. If one force is larger than the sum of the other two forces, then the minimum value of the resultant force is the sum of the maximum force minus the other two forces

6. Gravity can be decomposed along the inclined plane and vertical inclined plane first. The component force of the vertical inclined plane is balanced with the supporting force of the inclined plane. The pulling force only needs to balance the difference between the separation of gravity along the inclined plane and the friction force.

7. Do you understand the formula of torsional shear stress? namely τ= T ρ/ Ip
τ( max)=TD/(2Ip)， τ( Min) = TD1 / (2ip)
so τ( min)=(d1/D) τ( max)

8. Conversion
metric system
1t = 1000kg = 10000000g = 10000000mg
municipal system
1t = 2000jin = 20000 Liang = 200000 yuan

9. The maximum of the three forces is the direct addition of the three forces (maximum in the same direction)
the minimum of the three forces: if the sum of any two forces is greater than the third force, the minimum of the three forces is 0 (triangle). If not, the minimum resultant force is equal to the sum of two smaller forces minus the maximum force.