High school physics formula
1. Basic Law of Curve Motion
① condition: v0 and f do not coincide.
② Speed direction: tangential direction.
③ Bending direction: always turn from v0 direction to F direction.
Step 3 pull the boat's rope
② Falling height:
12 centripetal acceleration:
High school physics knowledge points
1. Force: Force is the interaction between objects.
1, and the international unit of force is Newton, which is represented by n;
2. Diagram of force: The directed line segment with arrow indicates the magnitude, direction and action point of force;
3. Schematic diagram of force: the direction of force is indicated by line segments with arrows;
4. 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 =? The magnitude of FN 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);
Second, vector: a physical quantity with both size and direction.
Such as force, displacement, velocity, acceleration, momentum and impulse.
Scalar: Physical forces with only magnitude and no direction, such as time, speed, work, power, distance, current, magnetic flux and energy.
Third, the condition that the object is in equilibrium (stationary uniform linear motion): the resultant force on the object is equal to zero;
1. If an object is in equilibrium under the action of three * * * point forces, the resultant force of any two forces is equal to the third force;
2. When an object is in an' equilibrium' state under the action of n * * * point forces, the resultant force of any nth force and (N- 1) forces is equal in the opposite direction;
3. The resultant force of an object in equilibrium in any two mutually perpendicular directions is zero.
High school physics learning methods
Attach importance to experiments
Physics is a science based on experiments, and many physical concepts and laws are summarized from experiments of natural phenomena. Doing more experiments can help us form correct concepts, enhance our ability to analyze and solve problems, and deepen our understanding of physical laws.
There are many demonstration experiments and student experiments in senior high school physics curriculum standards. For freshmen in senior high school, we should pay attention to these two experiments. For demonstration experiments, students should carefully observe and analyze the experimental phenomena according to the teacher's guidance, find out the purpose and principle of each experiment, and understand the performance and usage of some instruments.
For students' experiments, we must emphasize that everyone should do it, not not not do it? Audience? ; When doing experiments, we should abide by the operating rules, make clear the experimental steps, do experiments seriously, record the data carefully, and draw correct conclusions after correct processing and analysis. After class, students can follow the small experiments in the textbook (for example? Hanging method? Find the center of gravity) or? Do: measure the reaction time? Take the initiative to do experiments to improve your hands-on ability.
Be observant
Most students who are good at physics are diligent and observant. Therefore, they have strong curiosity and thirst for knowledge. For example, in the introductory class, we demonstrated the collision phenomenon of small iron balls. Some students not only simply observed the phenomenon that one ball collided with another ball, but also asked what would happen if two balls collided.
What happens when three balls collide with two balls? Why is this happening? Being diligent in observation and good at asking questions will definitely make you interested in physics and push yourself to read books, study and explore. Only in this way can we really be interested in physics.
When we study friction, we should observe the contact surface of the object (material, roughness, etc. ) in our daily life, and what is the difference between the friction between the wheels of racing cars and ordinary cars and the ground, so as to combine the phenomena in our daily life with the relevant knowledge of friction.
After learning inertia, I saw that when the car started or braked, the people in the car fell backward or forward, or when the car turned, the people in the car leaned out of the corner. Seeing this phenomenon should be related to inertia, so observation is targeted and targeted. Your brain must have stored a lot of physical phenomena and related physical knowledge.
Be diligent in thinking
Physics in senior high school has strong regularity and logic, and it is flexible to connect with practice. It is impossible to learn physics by rote. We must be diligent in thinking, increase understanding and master its laws. To do a physics problem, we must first understand its physical process, establish a correct physical scene, and analyze the conditions it meets, so as to correctly choose the physical laws, instead of simply solving the physics problem as a math problem.
Since the beginning of senior one, we have learned many basic concepts and formulas. Every time we learn a concept, we must find out: how did this concept come from? How is it defined? What is the physical meaning? What is the relationship between formula and other physical quantities? Whenever you learn a formula, try to find out: How did this formula come from? What are the applicable conditions and scope?