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Name _______________________________________________ Date ________________ Class______________
Chapter 8, continued
Section 2: What Is a Machine?
(p. 192)
1. The tools used to fix a flat tire are not complicated enough to be
called machines. True or False? (Circle one.)
Machines—Making Work Easier (p. 192)
2. Which of the following are machines? (Circle all that apply.)
a. scissors
b. lug nut
c. screw
d. car jack
3.
As you pry the lid off a can of paint, work is done
on the screwdriver and on the lid.
4.
While you pry off the lid with the screwdriver, you
are not doing any work.
5.
The force you apply to the screwdriver while prying
is the input force.
6.
The work output done by the screwdriver works
against the forces of weight and friction to open
the lid.
7.
The screwdriver helps you open the can because it
increases the amount of work you apply to the can.
CHAPTER 8
Mark each of the following statements True or False.
a.
b.
c.
d.
▼
▼
▼
Copyright © by Holt, Rinehart and Winston. All rights reserved.
8. How does using a ramp make lifting a heavy object easier?
The object is moved over a shorter distance.
The ramp increases the amount of work you do.
Less force is needed to move the object over a longer distance.
None of the above
9. When a machine shortens the distance over which a force is
exerted, the size of the force must
(increase or decrease)
.
Mechanical Advantage (p. 196)
10. By comparing the mechanical advantage of two machines, you
can tell which machine
a.
b.
c.
d.
is bigger.
has a larger output force.
has a larger input force.
makes work easier.
DIRECTED READING WORKSHEETS
57
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Lesson
Name _______________________________________________ Date ________________ Class______________
Chapter 8, continued
11. Chopsticks allow you to exert force over a longer distance, but
the mechanical advantage is
a. less than one.
b. equal to one.
c. greater than one.
d. impossible to determine.
Mechanical Efficiency (p. 197)
12. The work output of a machine is always less than the work
input. Where does the missing work go?
a. It is used to get the machine started.
b. It is used to overcome the friction created by using the
machine.
c. It is used to keep the machine running.
d. None of the above
13. A machine that has no friction to overcome is called
a. an ideal machine.
b. a complex machine.
c. a real machine.
d. a smooth machine.
Review (p. 197)
Now that you’ve finished Section 2, review what you learned by
answering the Review questions in your ScienceLog.
Section 3: Types of Machines
(p. 198)
Levers (p. 198)
Mark each of the following statements True or False.
2.
A first-class lever changes the direction of the input
force.
3.
The output force of a second class lever is smaller
than the input force.
4.
Third-class levers do not increase the input force.
Inclined Planes (p. 200)
5. You must divide the
of the
inclined plane by the
you are
lifting the load in order to calculate mechanical advantage.
6. An inclined plane saves the work required to lift an object.
True or False? (Circle one.)
58
HOLT SCIENCE AND TECHNOLOGY
Copyright © by Holt, Rinehart and Winston. All rights reserved.
1. Name the six simple machines.
Menu
Lesson
Print
Name _______________________________________________ Date ________________ Class______________
Chapter 8, continued
Section 2: What Is a Machine?
(p. 192)
1. The tools used to fix a flat tire are not complicated enough to be
called machines. True or False? (Circle one.)
Machines—Making Work Easier (p. 192)
2. Which of the following are machines? (Circle all that apply.)
a. scissors
b. lug nut
c. screw
d. car jack
3.
True
As you pry the lid off a can of paint, work is done
on the screwdriver and on the lid.
4.
False
While you pry off the lid with the screwdriver, you
are not doing any work.
5.
True
The force you apply to the screwdriver while prying
is the input force.
6.
True
The work output done by the screwdriver works
against the forces of weight and friction to open
the lid.
7.
False
The screwdriver helps you open the can because it
increases the amount of work you apply to the can.
CHAPTER 8
Mark each of the following statements True or False.
a.
b.
c.
d.
▼
▼
▼
Copyright © by Holt, Rinehart and Winston. All rights reserved.
8. How does using a ramp make lifting a heavy object easier?
The object is moved over a shorter distance.
The ramp increases the amount of work you do.
Less force is needed to move the object over a longer distance.
None of the above
9. When a machine shortens the distance over which a force is
exerted, the size of the force must
(increase or decrease)
increase
.
Mechanical Advantage (p. 196)
10. By comparing the mechanical advantage of two machines, you
can tell which machine
a.
b.
c.
d.
is bigger.
has a larger output force.
has a larger input force.
makes work easier.
DIRECTED READING WORKSHEETS
57
Menu
Print
Lesson
Name _______________________________________________ Date ________________ Class______________
Chapter 8, continued
11. Chopsticks allow you to exert force over a longer distance, but
the mechanical advantage is
a. less than one.
b. equal to one.
c. greater than one.
d. impossible to determine.
Mechanical Efficiency (p. 197)
12. The work output of a machine is always less than the work
input. Where does the missing work go?
a. It is used to get the machine started.
b. It is used to overcome the friction created by using the
machine.
c. It is used to keep the machine running.
d. None of the above
13. A machine that has no friction to overcome is called
a. an ideal machine.
b. a complex machine.
c. a real machine.
d. a smooth machine.
Review (p. 197)
Now that you’ve finished Section 2, review what you learned by
answering the Review questions in your ScienceLog.
Section 3: Types of Machines
(p. 198)
The six simple machines are lever, inclined plane, wedge, screw, wheel and
axle, and pulley.
Levers (p. 198)
Mark each of the following statements True or False.
2.
True
A first-class lever changes the direction of the input
force.
3.
False
The output force of a second class lever is smaller
than the input force.
4.
True
Third-class levers do not increase the input force.
Inclined Planes (p. 200)
5. You must divide the
length
of the
height
inclined plane by the
you are
lifting the load in order to calculate mechanical advantage.
6. An inclined plane saves the work required to lift an object.
True or False? (Circle one.)
58
HOLT SCIENCE AND TECHNOLOGY
Copyright © by Holt, Rinehart and Winston. All rights reserved.
1. Name the six simple machines.