How to explain the fact that although the weight is small, it can weigh a thousand pounds? Need to explain in detail.

Give you a fulcrum. Can you tilt the earth?

Also known as "leverage balance condition". In order to balance the lever, the magnitude of the two forces (force point, fulcrum and resistance point) acting on the lever is inversely proportional to their force arms. Power× power arm = resistance× resistance arm, which is expressed by algebra as f? 6? 1 L 1=W？ 6? 1L2. where f stands for power, L 1 stands for power arm, w stands for resistance, and L2 stands for resistance arm. As can be seen from the above formula, in order to balance the lever, the power arm is several times that of the resistance arm, and the power is a fraction of the resistance. When using a lever, in order to save labor, a lever with a power arm longer than a resistance arm should be used; If you want to save distance, you should use a lever with a force arm shorter than a resistance arm. Therefore, the use of levers can save manpower and distance. However, if you want to save energy, you must move more distance; If you want to move a shorter distance, you must work harder. It is impossible to save energy and move the distance.

It is from these axioms that Archimedes discovered the lever principle on the basis of the "center of gravity" theory, that is, "when two heavy objects are in equilibrium, their distance from the fulcrum is inversely proportional to their weight. Archimedes' research on lever not only stays in theory, but also makes a series of inventions according to this principle. It is said that he once made a mast landing on the beach with the help of lever and pulley block. In the battle to defend Syracuse from the Roman navy, Archimedes used the lever principle to make a catapult at a distance and a distance, and used it to launch various missiles and boulders to attack the enemy, which once prevented the Romans from entering Syracuse for three years.

Archimedes, an ancient Greek scientist, famously said, "If you give me a fulcrum, I can move the earth!" This sentence is not only an inspiring aphorism, but also has a strict scientific basis.

Archimedes first put forward the lever principle in the book On the Balance of Plane Figures. He first regarded some empirical knowledge in the practical application of leverage as "self-evident axioms", and then from these axioms, he used geometry and strict logical argumentation to draw the principle of leverage. These axioms are: (1) If equal weights are hung at both ends of a weightless bar at the same distance from the fulcrum, they will be balanced; (2) Hang unequal weights at the same distance from the fulcrum at both ends of the weightless bar, and the heavy end will fall; (3) Hang an equal weight at both ends of the weightless bar with different distances from the fulcrum, and the far end will incline downward; (4) The function of one weight can be replaced by the function of several evenly distributed weights, as long as the position of the center of gravity remains unchanged. On the contrary, several evenly distributed weights can be replaced by a weight hanging from their center of gravity; The center of gravity of the graph is also distributed in a similar way ... It is from these axioms that Archimedes discovered the lever principle on the basis of the theory of "center of gravity", that is, "when two heavy objects are in equilibrium, their distance from the fulcrum is inversely proportional to their weight."

Archimedes' research on lever not only stays in theory, but also makes a series of inventions according to this principle. It is said that he used to make the mast boat parked on the beach smoothly launch with the help of lever and pulley block. In the battle to defend Syracuse from the Roman navy, Archimedes used the lever principle to make long-range and short-range catapults, and used them to launch various missiles and boulders to attack the enemy, which once made the Romans stay outside Syracuse for three years.

Incidentally, there are also records about leverage in the history of our country. Mohist school in the Warring States period once summarized this law, and there are two special records about the principle of leverage in Mohist book. These two articles elaborated the balance of leverage very comprehensively. There are equal arms and unequal arms inside; Some change the weight of both ends to make it biased, and some change the length of the two arms to make it biased. Such a record is also very valuable in the history of world physics. Mozi's discovery was about 200 years earlier than Archimedes's.

Examples in life are: chopsticks, seesaw, hammer, can opener and so on.