What is the content of mechanics in junior high school physics?

Hello, the physics of the eighth grade is like this, first the change of the state of matter, not difficult, the mechanics of the eighth grade "Book II" is the pressure about what water, air, and the surface of the earth, etc., and then the third year of junior high school is the royal force of what lever is used, etc., good luck, hope.

Mechanical energy is the focus of high school, and simple forces such as gravity, friction, support, and pressure are the main ones in junior high school.

Physical quantity. Unit.

Formula. Name.

Symbol. Name.

Symbol. Quality. m kg.

kgm = pv temperature. t

Celsius. cspeed. v

Meter seconds. m/s

v=s t density.

p. kgm

kg/m³p=m/v

Force (gravity) f

Newton (Newton) n

g = mg pressure.

Pascal (Pa).

pap = f s work. w

Joule (Joule) J

w = fs power.

p watts (watts).

wp = w t current. i

Ampere (ampere) a

i=u r voltage.

U volts (volts) vu = IR

Resistance. r ohms (ohms) r = u i electrical work. w

Joule (Joule) J

w = uit electrical power.

p watts (watts).

wp=w/t=ui

: The main contents of physics and mechanics in junior high school are:

1.Force and machinery.

The concept of force, the measurement and representation of force, several common forces (gravity, elasticity, friction);

lever principle, pulleys and pulley blocks;

2.Force and movement.

Mechanical motion, Newton's first law, how an object moves when it is not subjected to force, equilibrium force and unbalanced force;

3.Pressure. Definition of pressure, characteristics of liquid pressure, atmospheric pressure.

4.Buoyancy vs. lift.

The definition of buoyancy, Archimedes' principle, the cause of lift.

There are several main aspects of physics and mechanics in junior high school:

1. Newton's first and third laws.

2. Pulleys and levers.

3. Liquid pressure.

4. Buoyancy.

There are several main aspects of physics and mechanics in junior high school:

1. Newton's first and third laws: The first law is that when all objects are not subjected to an external force or the combined external force is zero, their motion remains unchanged, including the state of constant linear motion and the state of rest in which the acceleration is always equal to zero, until an external force forces it to change. Newton's third law states that the force of action and reaction between two objects is equal in magnitude, opposite in direction, and in the same straight line.

2. Pulley and lever: A rod that can rotate around a fixed point under the action of a good brigade of force is called a lever. Fixed pulley definition:

The central shaft is a fixed pulley. The essence of the fixed pulley is: the equal arm lever.

Features: The use of fixed pulleys can not save effort but can change the direction of power. Definition of movable pulley:

Pulleys that move with heavy objects. Substance: The essence of the movable pulley is:

The power sock arm is a labor-saving lever that is twice that of the resistance arm. Features: The use of movable pulleys can save half of the force, but it cannot change the direction of power.

3. Liquid pressure: In the bottom, inner wall and interior of the liquid container, the pressure generated by the liquid is called liquid pressure, referred to as hydraulic.

4. Buoyancy: refers to the difference or resultant force of the pressure of each surface of the object in including liquid and gas.

The knowledge points of physics and mechanics in junior high school are summarized as follows:1. Elastic force or friction may occur between objects in contact with each other. On the other hand, the condition for the elastic force to occur is "contact and mutual extrusion to produce deformation".

2. There is also a strong effect between objects that are not in contact, such as the force of a magnet on iron, the effect of the earth on a bird flying in the air, etc., and we will learn about the force generated by this "field" in high school.

3. Concept: Force is the action of an object on an object.

4. Effect: force can change the motion state of the object; Force can change the shape of an object.

5. Unit: The unit of force in the International System of Units is Newton, referred to as the cow, which is represented by n.

6. The force experienced by an object near the ground due to the attraction of the earth is called gravity.

The knowledge points of physics and mechanics in junior high school are as follows:1. The three elements of force: the magnitude, direction, and application point of force are called the three elements of force.

The method of using a line segment with an arrow to represent all three elements of force is called the force diagram method. The length of the line segment indicates the magnitude of the force; The direction of the arrow indicates the direction of the force; The starting point of the segment represents the point at which the force is applied.

2. Inertia: We call the property of an object that keeps its state of motion unchanged as inertia.

3. When several forces act together on an object, their effect can be replaced by a force, which is called the resultant force of those forces. If the magnitude and direction of several forces are known, finding the magnitude and direction of the resultant force is called the synthesis of the force.

4. Rolling friction: The friction generated when an object rolls on another object is called rolling friction.

5. Transforming sliding friction into rolling friction can greatly reduce friction.

1. Quality m

2. Temperature t

3. Speed v

4. Density

5. Force (gravity) f

6. Pressure p

7. Power w8, power p

1. Force (f): Force is the action of an object on an object, and the action of force between objects is always reciprocal. Unit of force: Newton (n).

2. The three elements of force: The magnitude, direction, and point of action of force are called the three elements of force. The diagram of the force should be scaled; Schematic diagram of the force, not scaled.

3. Gravity g: The force experienced by an object due to the attraction of the earth. Directions:

Straight down. Gravity and mass relationship: g=mg m=g g, g=kN. kg.

Reading: Niu Xiang This kilogram of silver means that the gravity of an object with a mass of 1 kilogram on the earth is a cow.

Gravity, friction, elasticity, and buoyancy are common forces in junior high school, and they have different requirements for different forces

1. Gravity: It is necessary to grasp the force object of gravity, the magnitude, direction, application point of gravity and the influencing factors of gravity;

2. Friction: It is necessary to grasp the magnitude and direction of static friction, the direction of sliding friction, and the influencing factors of magnitude.

3. Elasticity: It is necessary to grasp the concept of elasticity. The magnitude and direction of the elastic force. Factors influencing the magnitude of elasticity.

4. Buoyancy: To grasp the concept of floating Kaili in the state stove. The magnitude and direction of buoyancy. Factors influencing the magnitude of buoyancy.

Hello, the forces involved in junior high school physics are gravity, lead, support, buoyancy, pull, elasticity, molecular force, and so on.

In high school, the centripetal force, the gravitational force of the mandarin orange, and the electromagnetic force will be added.

Gravity g, friction f, support fn, pull, elasticity, buoyancy.

Mechanics.

Electrodynamics, Quantum Mechanics, Classical Mechanics, Thermodynamics, Statistical Mechanics, Relativistic Mechanics, etc.

2] Mechanics; Mechanics is an independent basic discipline, and mechanics is a science that studies the laws of mechanical motion of matter. There are many levels of matter in nature, from the cosmic system of the universe, macroscopic celestial bodies and conventional objects, mesporal particles, fibers, and crystals, to microscopic molecules, atoms, and elementary particles. Mechanics, as it is commonly understood, is dominated by the study of natural or artificial macroscopic objects.

However, due to the interpenetration of disciplines, sometimes it also involves objects and related laws in the cosmic or mesoscopic or even microscopic levels. Their establishment and use is a comprehensive scientific and technological project in itself, which requires multi-disciplinary collaboration. Mechanics, also known as classical mechanics, is a natural science that studies the deformation of objects of normal size under force, as well as the process of motion at a speed much lower than the speed of light.

Mechanics is the foundation of physics, astronomy and many engineering sciences, and the rational design of machinery, architecture, spacecraft and ships must be based on classical mechanics.

Mechanics includes: kinematics [linear motion, curvilinear motion], statics [gravity, elasticity, friction and force synthesis, force decomposition, etc.], dynamics [Newton's laws of motion].

The two main blocks, statics and kinetics in the other are their branches.

Theoretical mechanics.

Mechanics of Materials. Hydrodynamics.

That is, the three laws, as long as you take care not to forget the force of acceleration.

The main thing is Newtonian mechanics, the three laws.