http://www.ck12.org Chapter 16. Work and Machines
16.2 Machines
Lesson Objectives
- Explain how machines help us do work.
- Define efficiency, and state how it is calculated.
- Define mechanical advantage, and state how it is calculated.
Lesson Vocabulary
- efficiency
- machine
- mechanical advantage
Introduction
When you hear the word "machine," do you think of large appliances, power tools, factory machines, or construction
equipment, like the examples pictured inFigure16.7? While all of these examples are machines, you might be
surprised to learn that devices as simple as hammers and screws are also machines. Why are these simple tools
considered machines? Read on to find out.
FIGURE 16.7
Do you know what type of work each of
these machines does?