Lesson Plan | Traditional Methodology | Dynamics: Newton's 3rd Law

Objectives

Duration: (10 - 15 minutes)

The purpose of this stage of the lesson plan is to present the learning objectives to the students, establishing a clear understanding of what will be covered during the class. This will help students focus on the most relevant information and have a clear direction about the skills they should acquire by the end of the class.

Main Objectives

1. Describe Newton's Third Law and its implications in the study of forces.

2. Identify the reactions of the main forces, such as the reaction of the weight force and the normal force.

3. Understand that every force has a reaction of the same magnitude and direction, but in opposite senses.

Introduction

Duration: (10 - 15 minutes)

The purpose of this stage of the lesson plan is to create an initial connection between theoretical content and practical situations in the students' daily lives. This will help spark interest and attention to the importance of the topic, laying the groundwork for a deeper understanding of the subsequent explanations about Newton's Third Law.

Context

To start the class on Newton's Third Law, it is important to contextualize the students with a practical scenario. For example, imagine two people skating on ice. When one pushes the other, both move in opposite directions. The person who pushes exerts a force on the other, and simultaneously, the second person exerts a force of the same magnitude, but in the opposite direction, on the first. This is a classic example of Newton's Third Law in action in everyday life.

Curiosities

An interesting curiosity is that Newton's Third Law is fundamental for the functioning of rockets. When a rocket releases gases backward, these gases exert an equal and opposite force that pushes the rocket forward, allowing it to take off and travel through space. Without this law, space exploration would be impossible!

Development

Duration: (45 - 55 minutes)

The purpose of this stage of the lesson plan is to deepen the students' understanding of Newton's Third Law by providing them with detailed and practical knowledge. By exploring concrete examples and solving problems, students will be able to identify and analyze action and reaction forces in different contexts, reinforcing their theoretical understanding with practical applications.

Covered Topics

1. Introduction to Newton's Third Law: Explain that Newton's Third Law states that for every action there is an equal and opposite reaction. Use the equation F₁ = -F₂ to illustrate this concept. 2. Action and Reaction in Everyday Life: Detail everyday examples where Newton's Third Law can be observed, such as pushing a wall, the functioning of rockets, and the interaction between feet and the ground when walking. 3. Examples of Forces and their Reactions: Explain how to identify pairs of action and reaction forces in practical situations. Show how weight force (gravity) and normal force are examples of action and reaction forces, with the Earth exerting a force on an object and the object exerting a force of equal magnitude and opposite direction on the Earth. 4. Problem Analysis: Demonstrate how to solve problems using Newton's Third Law. Use practical examples such as the interaction between two bodies, collisions, and systems of forces in equilibrium to illustrate the application of the law. 5. Impact of Newton's Third Law on Engineering and Technology: Discuss how Newton's Third Law is fundamental for the development of modern technologies. Exemplify with aerospace engineering, vehicle design, and other areas where understanding action and reaction forces is crucial.

Classroom Questions

1. Explain how Newton's Third Law applies when you push a wall. What are the forces involved and their directions? 2. A rocket is launched into space. Describe how Newton's Third Law explains the rocket's motion. 3. A soccer ball is kicked. Identify the action and reaction forces involved in this event and describe them.

Questions Discussion

Duration: (20 - 25 minutes)

The purpose of this stage of the lesson plan is to review and consolidate the students' understanding of Newton's Third Law. By discussing the answers to the presented questions and engaging students in additional reflections and questions, the teacher ensures that the concepts have been clearly understood and applied. This also allows for identifying possible doubts and reinforcing learning.

Discussion

• Explanation about pushing a wall: When you push a wall, you are applying a force on it. According to Newton's Third Law, the wall applies an equal magnitude and opposite direction force on you. The forces involved are: the force you exert on the wall (action) and the force the wall exerts on you (reaction). Both have the same magnitude but opposite directions.

• Explanation about launching a rocket: When a rocket is launched into space, the engines expel hot gases backward. These gases, being pushed backward, exert a forward reaction force on the rocket, according to Newton's Third Law. This reaction force is what propels the rocket upward and forward, allowing its movement and takeoff.

• Explanation about kicking a soccer ball: When a soccer ball is kicked, the player's foot exerts a force on the ball (action). In response, the ball exerts a force of equal magnitude and opposite direction on the player's foot (reaction). The action and reaction forces involved are: the force from the foot on the ball and the force from the ball on the foot.

Student Engagement

1. Ask: What are other everyday examples where we can observe Newton's Third Law in action? 2. Reflection: How can understanding Newton's Third Law help in engineering and technology projects? 3. Discussion: Think about a sport of your choice. How is Newton's Third Law present in that sport? 4. Ask: How does Newton's Third Law apply when you jump from a boat to the shore? What are the forces involved? 5. Reflection: Why is it important to understand Newton's Third Law when studying systems in equilibrium?

Conclusion

Duration: (10 - 15 minutes)

The purpose of this stage of the lesson plan is to review and consolidate the knowledge acquired by the students, ensuring that they understand the main points addressed and know how to apply them in practical situations. This final review helps to fix the content in memory and clarify any remaining doubts.

Summary

• Newton's Third Law asserts that for every action there is an equal and opposite reaction.
• Everyday examples, such as pushing a wall, the functioning of rockets, and the interaction between feet and the ground when walking, illustrate Newton's Third Law.
• Identification of pairs of action and reaction forces, such as weight force (gravity) and normal force.
• Solving practical problems using Newton's Third Law, such as the interaction between two bodies, collisions, and systems of forces in equilibrium.
• The importance of Newton's Third Law in engineering and technology, including aerospace engineering and vehicle design.

The class connected the theory of Newton's Third Law with practical everyday examples and solved problems, demonstrating how action and reaction forces are present in various daily situations and advanced technological applications.

Understanding Newton's Third Law is crucial for daily life, as it explains many everyday phenomena, such as why we can walk or how vehicles move. Furthermore, this understanding is vital for engineering and technology, allowing the development of innovative and efficient solutions.