What can be the effect of the lever rotation is called power??

Definition of leverage].

As long as a solid object is able to rotate around the support point under the action of force, it is a lever.

Nature of leverage].

The point of support around which the lever rotates is called the fulcrum.

The force that makes the rigid rod rotate is called the kinetic force, and the force that prevents the lever from turning is called resistance.

When the rotational effects of power and resistance on the lever cancel each other, the lever will be in equilibrium, and this state is called lever equilibrium.

The straight line in the direction of the force through the point of application of the force is called the line of action of the force.

The distance from the fulcrum to the line of action of the force is called the force arm.

The line of action distance L1 from the fulcrum O to the power F1 is called the power arm.

The distance from the line of action from the fulcrum O to the resistance F2 L2 is called the resistance arm.

Leverage Balance Condition].

Power Arm Power = Resistance Arm Resistance, i.e., L1F1 = L2F2, which can evolve to F2 F1 = L1 L2

Balance of leverage.

It is not only related to the dynamic force and resistance, but also to the point of action of the force and the direction in which it is acted.

1. The force that makes the lever rotate is called power.

2. Lever is also known as laborious lever, labor-saving lever and equal-arm lever, and the lever principle is also known as "lever balance condition". For a lever to be balanced, the magnitude of the two moments (the product of the force and the arm of the force) acting on the lever must be equal. Namely:

Power Power Arm = Resistance Resistance arm, expressed algebraically as f1·l1=f2·l2. where F1 represents the power, L1 represents the power arm, F2 represents the resistance, and L2 represents the resistance arm. From the above equation, it can be seen that to balance the lever, the power arm is several times that of the resistance arm, and the resistance is several times the power.

** In "On the Balance of Plane Figures".

The lever works around the fulcrum. A lever is a simple machine. A hard rod that rotates around a fixed point under the action of force is a lever.

In life, the lever can be of any shape according to the need. Seesaws, scissors, wrenches, crowbars, fishing rods, etc., are all levers. The pulley is a deformed lever, the essence of the fixed pulley is the equal arm lever, and the essence of the movable pulley is that the resistance arm is half of the labor-saving lever of the power arm.

Expansion: The Five Elements of Leverage.

Fulcrum: The point at which the lever turns, usually denoted by the letter O.

Power: The force that turns a lever, usually expressed as f1.

Resistance: The force that prevents the lever from turning, usually expressed as f2.

Power arm: The distance from the fulcrum to the line of action, usually expressed by L1.

Resistance arm: The distance from the fulcrum to the line of action of resistance, usually denoted by L2.

Answer]: A motor system is composed of bones, bone connections, and skeletal muscles. In exercise, the bone plays a role as a lever, the joint is the hub (fulcrum) of movement, and the bone burns the void and the iliac muscle is the power organ of movement.

A lever is a simple machine. A sturdy stick (preferably unbent and very light) can be used as a lever. In the picture above, the square represents the weight, the circle represents the support point, and the arrow represents the use, so you can see it, right? The downward lever to the right of the lever is the equiarm lever; The second is that the focus is in the middle, and the power arm is larger than the resistance arm, which is a labor-saving lever; The third is that the force point is in the middle, and the power arm is less than the resistance, which is a laborious lever.

Strenuous levers such as scissors, hammers, nail pullers, ......Leverage can be effortless or labor-intensive, or it may be neither labor-saving nor labor-intensive. It depends on the distance between the force point and the fulcrum:

The farther the force point is from the fulcrum, the more labor-saving, and the closer it is, the more laborious it is; It also depends on the distance between the key point (resistance point) and the fulcrum: the closer the key point is to the fulcrum, the more labor-saving, and the farther it is, the more laborious it is; If the focus and force point are as far away from the fulcrum, such as the fixed pulley and the balance, it will not save effort or effort, but only change the direction of force.

Labor-saving levers such as corkscrews, juicers, nutcrackers, ......This kind of lever force point must be closer than the key point from the fulcrum, so it is always labor-saving.

If we use flower scissors (the blade is relatively short) and foreign cutting knives (the blade is relatively long) to cut the cardboard, the flower scissors are more labor-saving but time-consuming; Tailoring, on the other hand, is laborious but time-saving.

1.Cut hard objects.

It takes a lot of force to cut through a hard object, which means that there is a lot of resistance. Use scissors with a long power arm and a short resistance arm.

2.Decoupage or cloth.

Soft objects such as paper or cloth can be cut with less force, which means that there is less resistance, and the knife edge needs to be longer in order to speed up the cutting speed. Use scissors with a short power arm and a long resistance arm.

3.Prune branches.

When pruning branches, on the one hand, the branches are hard, which requires the power arm of the scissors to be long and the resistance arm to be short; On the other hand, in order to speed up the pruning speed and cut neatly, the scissor edge is required to be long. Use scissors with a long power arm, a short resistance arm, and a long knife edge.

The earliest discoverer of the lever principle is generally believed to be Archimedes of ancient Greece, but this is not the case, Mozi of the pre-Qin period, whose real name was Mo Zhai, was the earliest discoverer; In other words, the earliest discoverers of the lever principle were Chinese, not ancient Greeks.

It is said that Archimedes described the principle of leverage in the form of axioms in his book "On the Equilibrium of Plane Figures", but Archimedes was born and died from 287 BC to 212 BC, which corresponds to the time before and after the destruction of the Six Kingdoms by Qin.

Mozi was born around the end of the Spring and Autumn Period (about 480 B.C.), and in 476 B.C., Mozi's "Book of Ink" has a detailed and precise description of the principle of levers.

The Book of Ink was completed in the 14th year of King An of Zhou (388 BC). The Book of Ink, also known as the Ink Debate. It is part of Mozi.

The Book of Ink predates On the Balance of Plane Figures by more than 100 years.

In addition, whether it is Mozi or Mojing, they are all inherited in an orderly manner, and they are conclusive pre-Qin historical documents, but Archimedes' writings are of unknown origin, and they were first discovered in the Renaissance period, about 1,500 years away from Archimedes' time, and the earliest version was a manuscript translated from Arabic into Latin, and there is not even an Arabic version, let alone an ancient Greek version, is it Archimedes' writing? Even if it's not an ancient Greek document, it's impossible to get to know.

Strictly speaking, it can only be regarded as a legend, just like the "Yellow Emperor's Neijing", which is said to be a record of the conversation between the Yellow Emperor and Qi Bolei Gong and others, but now everyone thinks that it is a work of posterity, and the real author is no longer available.

The lever has been used for a long time, it should be said that it was used when there was no human society, but Archimedes's sentence of prying the earth is too famous, now there are levers everywhere, levers are used all the time, levers are not what you understand, only in pry big stones and other aspects can save effort to use him, the biggest use of levers is transmission, any moving part of any machine is a lever, through the lever on both sides of the arm length is different, you can enlarge or reduce the distance of movement, if the fulcrum is in the middle, The direction of the driving force is opposite to the passive direction, if the fulcrum is at one end, the active and passive directions are the same, and the gear transmission is also a lever, and the transmission ratio can be changed through the length of the arm that is, the size of the gear diameter.

There is leverage everywhere in life.

The earliest should be Archimedes, the principle of leverage can save effort.