1. One of the three physics notes required in Senior Two.
Gravitational potential energy: the gravitational potential energy of an object is equal to the product of its weight and velocity. 1, and the gravitational potential energy is expressed by EP;
2. Mathematical expression of gravitational potential energy: EP = mgh.
3. Gravitational potential energy is scalar, and its international unit is Joule;
4. The gravitational potential energy is relative: its magnitude is related to the selected reference frame;
5. The relationship between gravitational work and gravitational potential energy.
(1) When an object is lifted, gravity does negative work and its potential energy increases;
(2) When an object falls, gravity does positive work and its potential energy decreases;
(3) The work done by gravity is only related to the height of the object at the beginning and end, and has nothing to do with the path of the object.
2. Senior two needs three physics notes.
Kepler's three laws: 1, Kepler's first law: all planets orbit the sun in ellipses, and the sun is at a focus of all ellipses;
Note: in middle school, unless otherwise specified, the trajectory of the planet is generally regarded as a circle;
2. Kepler's third law: all planets and the sun line sweep the same area at the same time;
3. Kepler's third law: the ratio of the cube of the semi-long axis of all planets to the square of period of revolution is equal; Formula: R3/T2 = K；;
3. Senior two requires three physical notes three.
Forces can be divided into gravity, elasticity, friction, molecular force, electric field force, magnetic field force, nuclear force and so on. (1) Gravity: the force exerted by the gravity of the earth on an object;
Gravity is not gravity, but an integral part of gravity;
(b) The direction of gravity is always vertical downward (downward perpendicular to the horizontal plane)
(c) The instrument for measuring gravity is a spring scale;
(d) The center of gravity is the equivalent point of each part of an object subjected to gravity, and only the center of gravity of an object with regular geometric shape and uniform mass distribution is its geometric center;
(2) Elastic force: the force exerted by the deformed object on the object in contact with it in order to restore deformation;
(1) Conditions for generating elastic force: two objects contact and deform; The deformation of the applied object generates elastic force;
(b) Elastic force includes: supporting force, pressure, thrust, pulling force, etc.
(c) The direction of supporting force (pressure) is always perpendicular to the contact surface and points to the supported or pressed object; The direction of tension is always along the contraction direction of the rope;
(d) Proportion of elastic force to deformation within elastic limit; F=Kx
(3) Friction: When two objects in contact with each other have relative motion or a trend of relative motion, the force that hinders the relative motion of the objects is called friction;
(a) Conditions for generating friction force: object contact, rough surface, squeezing, relative motion or relative motion tendency; Elastic force does not necessarily have friction, but there must be elastic force between two things with friction;
(b) The direction of friction is opposite to the relative motion (or relative motion trend) of the object;
(c) The magnitude of sliding friction force F-slip =μFN The magnitude of pressure is not necessarily equal to the gravity of the object;
(d) The magnitude of static friction is equal to the external force that causes the relative motion of objects;
(4) resultant force and component: if several forces have the same effect on an object as a force, then this force is called the resultant force of those forces, and those forces are called the component of this force;
(a) The resultant force has the same effect as the component force;
(b) The resultant force and component force follow the parallelogram rule: if two line segments representing forces are used as adjacent sides to form a parallelogram, then the diagonal line sandwiched between these two sides represents the resultant force of the two forces;
(c) The resultant force is greater than or equal to the difference between the two components and less than or equal to the sum of the two components;
(d) When the force is decomposed, it is usually decomposed according to its action effect; Or decompose the force along the direction (or movement trend) of the object and its vertical direction; (orthogonal decomposition method of force);
4. Senior two requires three physical notes four.
Quantization of energy 1, Establishment of quantum theory: 1900, German physicist Planck proposed that the energy of vibrating charged particles can only be an integer multiple of a certain minimum energy value ε, which is called energy quantum.
ε=hν
H is Planck constant (6.63× 10-34J. s)。
2. Blackbody: If an object can completely absorb incident electromagnetic waves of various wavelengths without reflection, it is an absolute blackbody, referred to as blackbody.
3. Blackbody radiation: The rule of blackbody radiation is that the higher the temperature, the higher the radiation intensity of various wavelengths, and the maximum radiation intensity moves in the direction of shorter wavelengths.
5. Senior two requires three and five physics notes.
Definition of speed: speed is a physical quantity that describes the speed of an object.
Instantaneous speed, average speed and average speed:
Instantaneous speed: the speed at which a moving object passes through a certain position or a certain moment, and its magnitude is called speed.
Average speed: the ratio of the displacement of an object to time in a certain period of time, which can roughly describe the speed of the object's movement.
The average speed is a vector, and the size of the average speed is related to the stage of the object's movement. Definition: v=s/t applies to all forms of exercise.
Average speed: the ratio of distance to time of an object in a certain time. The average rate is scalar. Definition: v = s/t.
Note: the average speed and the average speed are often unequal, and they are equal only when the object moves in a straight line without reciprocating motion.
6. Senior two requires three physical notes six.
Newton's laws of motion (Newton's first, second and third laws); One of the basic laws of mechanics: the law of universal gravitation;
Basic laws of celestial motion (planets, artificial earth satellites, three special satellites with gravity completely acting as centripetal force, near-polar synchronization and orbit change);
One of the basic laws of mechanics: momentum theorem and kinetic energy theorem (the relationship between force and object speed change-the relationship between impulse and momentum change-the relationship between work and energy change);
Law of conservation of momentum (four conservation conditions, equations and application process);
Basic relations of functions (work is a measure of energy conversion)
One of the basic laws of mechanics: the relationship between gravity work and the change of gravity potential energy (the characteristics of gravity, molecular force, electric field force and gravity work);
Functional principle (the relationship between non-gravity work and the change of mechanical energy of an object);
One of the basic laws of mechanics: the law of conservation of mechanical energy (conservation conditions, equations and application steps);
The basic law of simple harmonic vibration (two idealized models vibrate completely at the same time, four processes, five physical quantities, the symmetry of simple harmonic vibration, and the vibration period formula of a simple pendulum); Image application of simple harmonic vibration;
Propagation characteristics of simple harmonics; The relationship among wavelength, wave velocity and period; Image application of simple harmonic function.