Forces in Life Physics 100

Physics is the science most closely related to human production and life. It has become the bounden duty of physics teachers to connect physics knowledge with production practice and life practice in physics teaching, so that students can understand the application of physics knowledge in production and life practice as much as possible.

1. Extensive application of mechanical knowledge.

1 Application of gravity.

We live on Earth, and gravity is everywhere. For example, when the workers are building the wall, they often use the hammer line to check whether the wall is vertical, which is the principle that the direction of gravity is vertical downward; The lower end of the shuttlecock is made heavier, which is to lower the center of gravity to protect the feather during the fall; The driver of the car can continue to coast when the engine is turned off when going downhill, which is the use of gravity to save energy; In agricultural production, the seedling throwing technology also uses the direction of gravity to go straight down. Without gravity, the world would be unimaginable, water would not be poured into the mouth, people would not be able to fall back to the ground after jumping, flying dust would float in the air forever, and the whole natural world would be a cloud.

When teaching gravity, it is necessary to let students have a lively discussion, fully tap students' imagination, and know that gravity is closely related to the reality of our production and life.

2 Application of friction.

Friction is an important force, and it is widely used in the reality of social production and life. For example, when people walk, it is very difficult to walk on smooth ground, because the friction of the contact surface is too small; When the car skiddies uphill, sprinkle some rough stones or straw on the road, and the car can move forward smoothly, which is to increase the roughness and increase the friction; The sole is made into various patterns, which also increases the roughness of the contact surface and increases the friction; The roller skates worn by skaters are equipped with balls to change the sliding friction into rolling friction, so as to reduce the friction and increase the sliding speed; The purpose of adding lubricating oil to all kinds of machines is to reduce the friction between the gears and ensure the good operation of the machine. It can be seen that the production and life of human beings are actually related to friction, and beneficial friction should be fully utilized, and harmful friction should be avoided.

You should be able to put it together on your own.

1. There must be a road before the car reaches the mountain, and the boat is naturally straight to the bridge: similar to the principle of wind vane, the force area is large when it is horizontal, and the deflection occurs, and the stable stress state is maintained.

2. Four or two dialing a thousand catties: the principle of leverage.

3. The hearts of the people are united, and Mount Tai moves: when the direction of the component is the same, the resultant force is great.

4. A slap does not make a sound: the effect of force is mutual.

5. The hemp rope lifts the tofu and is resistant to orange, but it cannot be lifted: the force area is small and the pressure is strong.

6. Sitting on the ground and traveling 80,000 miles a day: the earth's rotation is about 1,000 kilometers, about 80,000 miles.

7. If you sit on pins and needles: the smaller the compression area, the greater the pressure.

8. When the egg hits the stone, it is not measured: the pressure of the object is different, and the pressure of the egg is small, so it is broken.

9. People go to high places, and water flows to low places: Gravity influences, water flows to low places.

10. Sharpen the knife and do not cut wood: reduce the pressure area and increase the pressure.

11. Mercury landing, pervasive: mercury has a high density and various substances on the ground, and has fluidity.

12. The big ship is leaking, and the mu bucket has in but not out: there is pressure in the liquid; Pressure inside the ship "Pressure in the water.

Definition: Force is the interaction between objects Magnitude, direction, and point of application are the three elements of force.

SI unit: Newton, abbreviated as bull, the symbol is nIt was named in honor of the British scientist Isaac Newton.

Properties: 1. Materiality: force is the effect of an object on an object, an object is affected by a force, there must be another object to exert this effect on it, and the force cannot be separated from the object and exist independently.

2. Reciprocity: The action between any two objects is always mutual, and the object applying force must also be the object under force.

The force can change the shape of an object and can also change the state of motion of an object.

1. The definition of physical force is that force is the interaction between objects, the direction of filial piety, and the point of action is the three-skin stupid silver element of force, the international unit is Newton, referred to as the ox, and the symbol is n, which is named in honor of the British scientist Isaac Newton.

2. Force is one of the basic concepts in mechanics, and it is the external cause that makes an object accelerate or deform. In dynamics, it is equal to the product of the mass of the object and the acceleration.

Cross talk "The Application of Quantum Mechanics in Cross Talk", the guy combines quantum mechanics and cross talk, and every sentence is high-energy.

It can be said that life is full of learning. Good at discovering.

According to the effect of force, it is classified as: tensile force, pressure, support force, power, resistance, attraction, repulsive force, centripetal force, buoyancy, etc.; According to the nature of force, it is classified as gravity, elastic force, friction force, gravitational force, molecular force, electric field force, magnetic field force, and various field forces.

Strong interaction force, weak interaction force, electromagnetic force, gravitational force.

In mechanics: gravity, elasticity, friction;

Molecular mechanics in thermal: electromagnetic force;

In atomic physics: nuclear force.

What is Force: Force is the action of an object on an object.

The action of forces between objects is mutual. (When an object exerts a force on another object, it is also subjected to the latter's force on it.)

Effect of force: Force can change the state of motion of an object and can also change the shape of an object. (A change in the shape or volume of an object is called a deformation.) )

The three elements of force are: the magnitude, direction, and point of action of the force, which are called the three elements of force, and they can all affect the effect.

Gravity: The force exerted by an object near the ground due to the attraction of the earth is called gravity. The direction of gravity is always straight downward.

Friction: When two objects in contact with each other are about to occur or have been in relative motion, a force will be generated on the contact surface that hinders the relative motion, which is called friction.

The amount of sliding friction is related to the roughness and pressure of the contact surface. The higher the pressure and the rougher the contact surface, the greater the sliding friction.