http://www.ck12.org Chapter 4. Motion and Forces
Vocabulary
- compound machine: Machine that consists of more than one simple machine.
Explore More
Do the simple and compound machines quiz at the following URL. Be sure to check your answers.
http://www.quia.com/pop/36483.html?AP_rand=58166172
Review
- What is a compound machine?
- What simple machines are found in a wheelbarrow? How do they make it easier to carry heavy objects?
- A pair of scissors is an example of a compound machine. Label the simple machines in the pair of scissors in
theFigure4.95.
FIGURE 4.95
- Why do compound machines tend to have lower efficiency but greater mechanical advantage than simple
machines?
Summary
This unit includes the concepts of motion, speed, velocity, and acceleration. Forces are introduced, including friction,
gravity, elastic force, and forces in fluids. Newton’s laws of motion are examined in detail. The unit also defines
work and power, and explains how machines help us do work.