Ch 21: Praxis General Science: Work, Energy & Power

About This Chapter

As you study for the Praxis General Science exam, use this chapter to improve your understanding of the relationships between work, force and energy. You can also examine the physics behind simple machines and review the concept of power.

Praxis General Science: Work, Energy & Power - Chapter Summary

Through this series of engaging lesson videos, you will be able to follow along with our professional instructors as they explain the characteristics of work, variable force, energy and power. These lessons will also help you review the ways in which energy and work relate to simple machines. As a result of studying these lessons, you should be ready for questions on the Praxis General Science exam regarding:

  • The definition and characteristics of work
  • Variable force and work
  • Applications of the work-energy theorem
  • Types of simple machines
  • Mechanics behind pulleys
  • Mechanical energy and the conservation of it
  • Power and the calculation for power

In addition to animated videos, you'll find transcripts and worksheets in the chapter. If you have questions about any of the material, you can ask questions of the science experts by submitting them interactively. Multiple-choice quizzes are provided to help you test your knowledge of work, energy and power.

7 Lessons in Chapter 21: Praxis General Science: Work, Energy & Power
Test your knowledge with a 30-question chapter practice test
Work: Definition, Characteristics, and Examples

1. Work: Definition, Characteristics, and Examples

Pushing a wall all day may feel like work, but unless you get that wall moving you're not doing any work according to the rules of physics. In this video lesson, you'll learn how work is defined as well as how to calculate the amount of work done on an object.

Work Done by a Variable Force

2. Work Done by a Variable Force

Doing work on an object is a simple concept: we apply a certain force over a certain distance. But in real life, that force is rarely constant. Therefore, we need to understand variable forces and be able to calculate them accurately.

Work-Energy Theorem: Definition and Application

3. Work-Energy Theorem: Definition and Application

Work and energy are closely related in physics. In this lesson, you'll learn what that relationship is as well as how we can apply it to various situations.

What Are Simple Machines? - Definition, Types & Examples

4. What Are Simple Machines? - Definition, Types & Examples

If you need to move or lift a heavy object, it would be wise to use a simple machine. Though these devices are far from fancy or high-tech, they are extremely helpful for getting work done.

Pulleys: Basic Mechanics

5. Pulleys: Basic Mechanics

Like other simple machines, pulleys can help us lift and move heavy loads with less effort. In this video lesson, you'll learn how pulleys do this as well as how this is possible while still obeying the law of conservation of energy.

Conservation of Mechanical Energy

6. Conservation of Mechanical Energy

Energy comes in many forms and for any system can never be created or destroyed. This holds true for mechanical energy, which also obeys this law of conservation of energy. In this video lesson, you'll explore how mechanical energy is converted or transferred between forms and objects.

Power: Definition and Mathematics

7. Power: Definition and Mathematics

Work involves moving an object with a force, but power tells us how quickly that work is done. In this lesson, you will learn about how power depends on both work and time as well as see examples of how to calculate power.

Chapter Practice Exam
Test your knowledge of this chapter with a 30 question practice chapter exam.
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Practice Final Exam
Test your knowledge of the entire course with a 50 question practice final exam.
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