Teaching plan of Newton's second law in senior high school physics 1
Textbook analysis
This chapter divides the inquiry experiment and formula expression of Newton's second law into two sections, aiming at strengthening experimental inquiry and highlighting the important position of Newton's second law in mechanics. The primary value of Newton's second law should be to establish a direct relationship between force and motion, that is, causality. If we know the force of the object, the motion state and its change of the object will be completely determined. This should be an important ideological achievement made by human beings in the process of understanding nature.
In this section, firstly, on the basis of the experiment in the last class, through analysis and explanation, the specific content expression of Newton's second law is put forward and the mathematical expression of Newton's second law is obtained. From SHAPE MERGEFORMAT to SHAPE MERGEFORMAT, to F=kma, and finally to F=ma, it contains rich knowledge and skills, processes and methodological goals. Therefore, we should pay more attention to the influence on students' concepts and psychology, that is, let students feel the essence, profundity and effectiveness of physics in understanding nature. The textbook highlights the physical meaning of the unit of force 1N, preparing for studying the content of the unit system later. Guide the students to have the necessary discussion. Finally, this section introduces the basic idea of applying Newton's second law through two examples, which is also the basic part of learning and understanding Newton's second law.
Analysis of learning situation
Before learning these contents, students have mastered the concepts of force, mass, acceleration and inertia. Know that mass is a measure of inertia, and force is the reason to change the motion state of an object; Will analyze the force of the object. They have mastered certain experimental operation skills, students have a certain understanding of physics research methods, and their ability of independent learning and cooperative inquiry has been improved to some extent.
In terms of non-intelligence factors, students are active in learning and have a strong interest in learning physics; Strong curiosity and thirst for knowledge, willing to explore the mysteries of nature; Dare to adhere to correct views and correct mistakes; I like studying with my peers and have a desire to exchange views with others.
Teaching objectives
I. Knowledge and skills
1. Master the text content and mathematical formula of Newton's second law.
2. Understand the meaning and relationship of each physical quantity in the formula.
3. Know how the unit of force "Newton" is defined in the international system of units.
4. Will use the formula of Newton's second law to make relevant calculations.
Second, the process and methods
1. Based on experiments, the relationship between the acceleration of an object and its mass and external force is summarized, and then Newton's second law is summarized.
2. It is an important method to know the laws of physics through experiments.
Third, emotional attitudes and values
1. Experimental inquiry stimulates students' curiosity and innovative spirit.
2. Infiltrate the education of physical research methods and experience the charm of physical methods.
Emphasis and difficulty in teaching
Teaching focus:
1. Guide students to explore the process of the relationship between acceleration, force and mass, and summarize Newton's second law.
2. The application of Newton's second law.
Teaching difficulties:
1. The meaning of Newton's second law.
2. When k= 1 is understood, F=ma.
teaching method
1. Inspiration and guidance, experimental exploration, cooperation and exchange.
2. Through case analysis and intensive training, let students understand the meaning of Newton's second law.
training/teaching aid
Newton's second law demonstrator, handcart (two), hook code (50g), thin thread, triangle.
Class arrangement
1 class hour
Teaching content, student activities
Last class, the students did an experiment in the laboratory to explore the relationship between acceleration and force and mass. Did the students analyze the experimental data? Have you reached any conclusions? Now, please draw a-F and embed it in the equation. DSMT4 image on the blackboard.
At the same time, the teacher demonstrated the relationship between acceleration and force and mass with Newton's second law demonstrator.
Experimental conclusion: acceleration is directly proportional to force and inversely proportional to mass.
New curriculum teaching
New curriculum teaching
I Newton's second law
Through the analysis and summary of the students' experimental conclusions in the last class, can students simply summarize the contents of Newton's second law?
So we all know that acceleration is a vector, so what is the direction of acceleration in Newton's second law?
So our complete definition of Newton's second law is:
The acceleration of an object is directly proportional to the force and inversely proportional to the mass, and the direction of acceleration is the same as that of the force.
Newton's second law can be expressed in proportion.
Embedding equation. DSMT4
rule
or
The above formula is a proportional formula. If written as an equation, how to express it?
Expression: F=kma
Where k is the proportional coefficient and f is the resultant force on the object.
Second, the unit of force.
Students already know that the unit of force is Newton in junior high school, but do students know how strong a Newton is?
By F=kma
When k= 1, F=ma.
Take m= 1kg a= 1m/s2.
Then: f = ma =1kg×1m/S2 =1kg m/S2.
Kilometers /S2 is the unit of force. We stipulate that 1 kg m /S2 is a unit force. To commemorate Newton, we call a unit force 1 Newton, so1n = 1kg m/S2, which means that a Newton's force is equivalent to a force of 1 m on an object with a mass of1kg.
So when M and A take international units, K= 1, and Newton's second law is expressed as: F=ma.
Definition: The acceleration of an object is directly proportional to the force it receives and inversely proportional to its mass.
The direction of acceleration is the same as the direction of the force acting on the object.
Because of these three factors, mass is scalar and force and acceleration are vectors.
The student got up and answered:
F=kma
Senior high school physics Newton's second law teaching plan daquan II
First, the teaching objectives
1, master the text content and mathematical formula of Newton's second law;
2. Understand the meaning and relationship of each physical quantity in the formula.
3. Know how the unit of force "Newton" is defined in the international system of units.
Second, the focus of teaching
1, knowing the factors that determine the acceleration of an object,
2. The process of exploring the relationship between acceleration and force and mass.
Third, teaching difficulties
1, understand the meaning and relationship of each physical quantity of Newton's second law.
2. The application of Newton's second law
Fourth, teaching methods.
In the process of inquiry, the research methods of infiltration science are: controlled variable method, experimental induction method, image method and so on.
Teaching process of verbs (abbreviation of verb)
1, knowledge review
The motion state of an object changes, that is, acceleration is generated.
Ask the students: What are the factors related to acceleration?
Students answer: force and the mass of the object.
Thinking: Force is the reason to change the motion state of an object, and it seems to "promote" the acceleration. Mass is a measure of the inertia of an object, and inertia is the property of keeping the motion state of the object unchanged, so mass seems to hinder the generation of "acceleration".
Guess: acceleration may be related to force and mass.
Combined with reality:
Automobile: Small mass, small inertia, and relatively easy to change when starting.
Train: It has great mass, great inertia and great power, and its motion state is relatively difficult to change when starting.
2. Recall what you learned in the textbook.
(1), the mass m is constant, and the relationship between acceleration a and force f.
Processing data: draw the conclusion that when m is constant, a and f are proportional,
Namely: a F
Shape merging format
(2) When the force f is constant, the relationship between the acceleration a and the mass m.
Shape merging format
It is concluded that when the force f is constant, the acceleration a is inversely proportional to the mass m, that is, a.
3. Introduce Newton's second law.
Through a large number of experiments and observed facts, we can draw the same conclusion, from which we can draw a general law: the acceleration of an object is directly proportional to the force it receives and inversely proportional to the mass, and the direction of acceleration is the same as that of the force, which is Newton's second law.
Senior high school physics Newton's second law teaching plan daquan III
The position and function of teaching materials
The content of this section is to explore and summarize the knowledge based on the last experimental lesson "Exploring the relationship between acceleration, mass and force", which requires knowing the factors that determine acceleration and understanding the relationship between acceleration, mass and force. It is required to experience inquiry activities, try to solve problems and experience the process of discovering laws. Newton's second law organically combines mechanics and kinematics, and specifically and quantitatively answers the relationship among acceleration, force and mass, which is the core content of dynamics and the key content of this chapter.
Analysis of learning situation
Before learning this section, students have mastered the concepts of force, mass, acceleration and inertia. Know that mass is a measure of inertia, and force is the reason to change the motion state of an object; Able to analyze the stress of objects; By discussing the relationship between acceleration and force and mass in the last section, we know the relationship between acceleration and force and mass All these have prepared the knowledge foundation for the study of this section. Newton's second law closely links the motion and force of an object through acceleration, making the first three chapters form a whole, which is an important tool to solve mechanical problems. Students should clearly understand Newton's second law and master it comprehensively.
Teaching objectives
1, knowledge target
(1) Understand the relationship between acceleration and force and mass.
(2) Understand the content of Newton's second law and know its exact meaning.
(3) Be able to use Newton's second law to answer related questions.
2. Ability objectives
Cultivate students' analytical ability, inductive ability and problem-solving ability.
3. The goal of moral education
(1) Education on research methods of infiltration physics.
(2) It is recognized that it is an important method to summarize the laws of physics through experiments.
(3) Cultivate students' critical thinking ability and stimulate students' interest in learning physics.
Teaching focus
Understanding Newton's second law
Teaching difficulties
Application of Newton's second law
Teaching strategy
Reviewing and thinking → creating physical scenes → group discussion → teacher's explanation → summarizing laws.
Teaching flow chart
Teaching process design
Teaching links and
A summary of the research on the design intention of teachers' activities and students' activities
Recall the relationship between a and f and m discussed last class. Question to students: Recall the content of the last experimental inquiry class and the application of the control variable method? What physical quantities have we learned? What is the relationship between them? Can we use formulas to reflect their relationship? Recall the knowledge of last class and answer collectively. Recall the relationship between a and f and m discussed last class. Create scenarios and introduce new courses
Question 1. Why did the Shenzhou VI spacecraft open its parachute when it returned to the capsule?
Question 2: What happened to the car at the moment it started? Guide students to think about two problems.
Further guide students to think: What is the difference in quality between racing cars and ordinary family cars? Why is this design? Discuss in groups, and each group sends representatives to answer questions. Through this question, students can easily think that the smaller the mass, the easier it is to change the state of motion, so the acceleration is related to the mass and external force of the object. New curriculum process
Newton's second law:
1, content: the acceleration of an object is directly proportional to the applied external force and inversely proportional to the mass of the object, and the direction of acceleration is the same as that of the applied external force.
2. formula: F=ma?
Q: What is the international unit of force? How is it stipulated? Establish a physical model and put forward the details that need attention.
Explanation: K is a proportional constant, so what should K be?
Teacher's summary: Force is the cause of object acceleration, and the international unit of force is1n =1kg m/S2. Students discuss and analyze in groups.
Students answer after summarizing themselves, and the incomplete places are supplemented by other students. Through the relationship among A, F and M explored in the previous section, the law is summarized by using experimental data, and the students' independent thinking ability and the spirit of respecting physical facts are cultivated. 3. Explain the characteristics of this law, so that students can have a further understanding of Newton's second law.
Six characteristics ① law of causality (force is the primary cause of acceleration), = 2 GB3 ② vector (both A and F are vectors, the direction of A is determined by F, and the decomposition and synthesis of force follow the parallelogram law), = 3 GB3 ③ instantaneity (the resultant force disappears, that is, A disappears), = 4 GB3 ④ relativity (Newton's second law only applies to inertial system), = 5 GB3 ⑤ independence (. Question: What are the characteristics of Newton's second law?
Based on the relative understanding of Newton's second law, six properties of the expression F=ma are discussed with vivid examples.
According to students' questions about relevant characteristics, give examples. Students discuss, try and answer the characteristics put forward by the teacher.
Students will ask questions about related characteristics in the process of learning. Exploring the characteristics of Newton's second law can deepen students' understanding of the essence of Newton's second law and make the previous knowledge coherent, which is of great help to solving problems or the practical application of Newton's law. 4. It takes methods to do the problem. Give students the steps to solve the problem according to the general idea of doing the problem. ① Determine the research object; ② Make a correct force analysis or motion analysis for the research object; (3) According to the formula and given conditions (pay attention to the hidden conditions), solve the required physical quantities.
For example, an object with a mass of 2 kg is subjected to two forces F 120 and f 2. The magnitude of these two forces is 10N. What is the acceleration caused by these two forces?
Classroom training P 104 exercises 1, 2, 3 teachers ask questions, guide students to get the steps to solve problems, and make appropriate supplementary explanations.
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