Objectives (5 - 7 minutes)

1. Understand the concept of force impulse and its relationship with the variation of a body's momentum.

2. Apply the impulse formula (I = F * Δt) to calculate the impulse of a force.

3. Relate the application of force, the time of application, and the variation of a body's momentum using practical examples.

Secondary Objectives:

• Develop problem-solving skills, encouraging students to apply the concept of impulse in everyday situations.

• Promote group discussion and collaboration among students through practical activities and classroom discussions.

Introduction (10 - 15 minutes)

1. Review of Previous Concepts: The teacher should start the lesson by reviewing the concepts of force and momentum that were previously studied. It will be important to clarify doubts and ensure that all students have a good understanding of these basic concepts.

2. Problem Situations: The teacher should propose two problem situations that arouse the students' interest and lead them to question how the impulse of a force can affect a body's momentum. The problem situations can be:

   • A soccer player kicking the ball: How does the force of the kick and the contact time with the ball affect the ball's speed after the kick?

   • A moving car braking suddenly: How does the friction force between the tires and the road, and the time it takes for the car to stop, affect the variation of the car's momentum?

3. Contextualization: The teacher should explain that the concept of impulse is widely used in physics, engineering, sports, and various other areas of knowledge. For example, in soccer, players use impulse to kick the ball with more force. In engineering, impulse is used to design efficient braking systems in vehicles.

4. Capturing Students' Attention: The teacher should present two curiosities related to the impulse of a force:

   • Curiosity 1: The world record for hammer throwing is 86.74 meters. Athletes break this record by applying a huge force to the hammer for a short period of time, thus increasing the impulse and, consequently, the momentum of the hammer.

   • Curiosity 2: In space, where there is no air or friction, a small impulse can make an object move at a very high speed. This happens because, in the absence of external forces, the momentum of an object remains constant.

Development (20 - 25 minutes)

1. Practical Activity 1 - Ball Kick (10 - 15 minutes): The teacher should divide the class into groups of 5 students. Each group will receive a soccer ball. The teacher should guide the students to plan an experiment to measure the ball's speed after a kick. The students should vary the force of the kick and the contact time with the ball, and record the ball's speed after the kick. The objective of the activity is for the students to observe the relationship between the applied force, the contact time, and the final speed of the ball, and understand how impulse affects the ball's momentum.

   • Step 1: Experiment planning: Students should discuss among themselves and decide how they will vary the force of the kick and the contact time with the ball. They should think of ways to measure the ball's speed after the kick.

   • Step 2: Experiment execution: Students should carry out the experiment according to the plan. They should record the force of the kick, the contact time, and the final speed of the ball.

   • Step 3: Results analysis: Students should analyze the collected data and try to find a relationship between the force of the kick, the contact time, and the final speed of the ball.

2. Practical Activity 2 - Car Braking (10 - 15 minutes): The teacher should propose another experiment for the students. Each group will have a toy car and a smooth surface to conduct the experiment. The students should vary the braking force applied to the car and the time it takes for the car to stop, and record the variation of the car's momentum. The objective of this activity is for the students to observe the relationship between the braking force, the braking time, and the variation of the car's momentum, and understand how impulse affects the car's braking.

   • Step 1: Experiment planning: Students should discuss among themselves and decide how they will vary the braking force and the braking time of the car. They should think of ways to measure the variation of the car's momentum.

   • Step 2: Experiment execution: Students should carry out the experiment according to the plan. They should record the braking force, the braking time, and the variation of the car's momentum.

   • Step 3: Results analysis: Students should analyze the collected data and try to find a relationship between the braking force, the braking time, and the variation of the car's momentum.

Return (8 - 10 minutes)

1. Group Discussion (3 - 4 minutes): The teacher should invite each group to share the conclusions they reached during the practical activities. Each group will have a maximum of 3 minutes to present. During the presentations, the teacher should ensure that all students are attentive and encourage them to ask questions or make comments. The objective of this stage is for students to learn from each other and consolidate what they have learned.

2. Connection with Theory (2 - 3 minutes): After the presentations, the teacher should briefly review the practical activities, highlighting how they are related to the theory of force impulse. The teacher should emphasize the importance of understanding the concept of impulse and how it is related to a body's momentum. The teacher can use examples from the practical activities to illustrate the theory.

3. Individual Reflection (2 - 3 minutes): The teacher should suggest that students make a brief reflection on what they learned during the lesson. For this, the teacher should ask the following questions:

   1. What was the most important concept you learned today?
   2. What questions have not been answered yet?

   Students should write down their answers on a piece of paper, which will be handed to the teacher at the end of the lesson. The objective of this stage is for students to reflect on what they have learned and identify any points that are still unclear to them. The students' answers will be valuable for the teacher to plan future lessons and review concepts that have not been understood.

4. Teacher's Feedback (1 minute): To conclude, the teacher should provide general feedback on the class's participation and performance during the lesson. The teacher should praise the students' efforts, highlight the positive aspects, and suggest improvements for future lessons. The teacher should encourage students to continue studying and making an effort to understand physics concepts.

Conclusion (5 - 7 minutes)

1. Content Recap (2 - 3 minutes): The teacher should summarize the main points covered in the lesson, reinforcing the concept of force impulse and its relationship with the variation of a body's momentum. The teacher should also recall the impulse formula (I = F * Δt) and how it can be applied to calculate the impulse of a force. The teacher should emphasize the observations and conclusions made during the practical activities, highlighting how they illustrate the concept of impulse.

2. Connection between Theory, Practice, and Applications (1 - 2 minutes): The teacher should emphasize how the lesson connected the theory of force impulse with the practice of experimental activities. It should also highlight the applications of the impulse concept in everyday situations, such as in sports (ball kick) and engineering (car braking). This will help students understand the relevance of what they have learned and apply the acquired knowledge in different contexts.

3. Extra Materials (1 minute): The teacher should suggest some additional study materials for students who wish to deepen their knowledge of force impulse. These materials may include explanatory videos, physics books, science education websites, among others. The teacher should encourage students to explore these materials on their own as a way to reinforce learning and clarify any doubts.

4. Subject Importance (1 minute): To conclude, the teacher should emphasize the importance of the subject presented for daily life and for science. It should emphasize how understanding force impulse can help understand various physical phenomena and apply science in practical situations. The teacher should reinforce that physics is not just a set of formulas and abstract concepts, but a powerful tool to understand the world around us.