260
Technology: Engineering Our World
Finding the Meaning of Unknown Words
Copy the following graphic organizer onto a separate sheet of paper. In
the left column, record words from the chapter that you do not understand. As
you read the chapter, try to guess their meanings and record your guesses in
your chart. After you have read the chapter, look up each word in a dictionary.
How close were your guesses? After you look up each word, go back and
reread that portion of the chapter. Do you understand the chapter better?
Unknown Word What I Think the Word Means Dictionary Definition
Write your answers to these review questions
on a separate sheet of paper.
1. When you hit a ball with a baseball bat, the
bat is an example of a lever. Explain why.
2. Explain which of the following is an
example of a Class 1 lever, and why:
nutcracker, wheelbarrow, hockey stick,
scissors.
3. A lever is used to move a load of
1500 newtons with a force of 300 newtons.
What is the mechanical advantage of
the lever?
4. A laborer using a Class 1 lever places the
load the same distance from the fulcrum
as the effort. If the fulcrum is moved
closer to the load, what happens to the
mechanical advantage?
5. What force would be required to raise
a load of 15 newtons using a single,
movable pulley?
6. List three examples of a wheel and axle.
7. List three practical applications of an
inclined plane.
8. A 100 N load has to be moved to the top
of an inclined plane that is 10 m long and
2 m high. What effort is required?
9. Explain the difference between a wedge
and an inclined plane.
10. What is the connection between an
inclined plane and a screw thread?
11. A gear is a modified form of which
simple machine?
12. Describe three common uses for gears.
13. The wheel in a two-gear train has 60 teeth,
and the pinion has 15 teeth. What is the
ratio of the gear train?
14. Sketch a simple gear train in which the
first and last gears are rotating in the
same direction. Use arrows to show
the direction of rotation of each gear.
15. How is pressure calculated?
16. What is the difference between hydraulics
and pneumatics?
17. What is the difference between work
and power?
18. Name the four basic kinds of motion and
give one practical example of each.
19. List two benefits and two disadvantages
of friction.
20. List three ways in which the friction
between two objects can be reduced.