Contextualization

Mechanical Energy is a fundamental concept in physics and encompasses two main forms of energy: kinetic energy, energy possessed by a body due to its motion, and potential energy, which is the energy that a body possesses due to its position or state.

Kinetic energy is calculated through the equation KE = 1/2mv², where m is the mass of the object and v is its velocity. On the other hand, potential energy is a form of energy that results from the position or configuration of an object. Potential energy can be gravitational (related to the position of an object in relation to Earth), elastic (associated with the deformation of an object), or chemical (associated with the composition of an object).

The principle of conservation of energy, which states that energy cannot be created or destroyed, only transformed, is of paramount importance for the understanding of physical systems and is a key component of the design.

In the real world, mechanical energy is applicable in numerous situations, whether in the study of the forces involved in the launch of a rocket or in understanding how a windmill generates energy. Therefore, understanding how energy is transformed and conserved is essential for many professions, such as engineering, meteorology, architecture, and even sports.

Furthermore, awareness of energy transformations is crucial for understanding current needs for sustainability and energy efficiency. Understanding how energy is used and transformed can help develop more efficient and sustainable technologies in the future.

Recommended Resources

• Book: "Fundamentals of Physics: Gravitation, Waves, and Thermodynamics", by David Halliday, Robert Resnick, and Jearl Walker - Chapter 7: Kinetic Energy and Work
• Website: Khan Academy Mechanical energy and conservation of energy
• Video: What is mechanical energy? - Mundo da Física Channel on Youtube
• Article: Mechanical Energy - Brasil Escola

Practical Activity

Activity Title: "Exploring Mechanical Energy: From Pendulum to Rocket"

Project Objective

The objective of this project is to explore the concepts of mechanical energy (kinetic energy and potential energy) and conservation of energy, and make connections with other areas of knowledge, such as mathematics and chemistry. Students will create and analyze three practical experiments to understand how energy is transformed and conserved.

Project Description

Divided into groups of 3 to 5 students, the students will carry out three main activities:

1. Simple Pendulum: In this experiment, students will build a simple pendulum to study the transformations of potential energy into kinetic energy and vice versa.

2. Elastic Catapult: Here, students will design and build a simple catapult using elastics and study the transformation of elastic potential energy into kinetic energy.

3. Water and Air Rocket: In this activity, students will build a simple "rocket" using a plastic bottle, water, and compressed air, and study the transformation of gravitational potential energy and chemical energy into kinetic energy.

For each experiment, the groups must calculate and analyze the mechanical energy involved and verify the conservation of energy.

Required Materials

1. Simple Pendulum: string, metal sphere, ruler, stopwatch.
2. Elastic Catapult: elastics, popsicle sticks, bottle cap, tape, ruler, scale.
3. Water and Air Rocket: PET bottle, air pump (or bicycle pump), water, stopwatch, measuring tape.

Step-by-Step for Activity Execution

The procedure details for each experiment, including how to calculate and analyze mechanical energy and energy conservation, will be provided in a separate guidance document.

Project Delivery

Each group must submit a detailed project report, containing four main parts:

1. Introduction: students must contextualize the experiments carried out, explaining the relevance of the concept of mechanical energy and its application in the real world.

2. Development: here students must explain each experiment in detail, including the related theory, the methodology used, and the energy calculations performed. The results obtained must be discussed and compared with the theory.

3. Conclusion: students must summarize the main points of the work, explaining the learnings obtained and the conclusions drawn from the project.

4. Bibliography: students must indicate the sources consulted to develop the project, such as books, web pages, videos, etc.

The report will be the main deliverable of the project and must reflect both the practical work carried out and the understanding of the theoretical concepts involved. It will be evaluated based on the clarity, comprehensiveness, and correctness of content and the interpretation and analysis of the results of the experiments.