Glencoe Science
Chapter Resources
Work and Machines
Includes:
Reproducible Student Pages
ASSESSMENT
TRANSPARENCY ACTIVITIES
✔ Chapter Tests
✔ Section Focus Transparency Activities
✔ Chapter Review
✔ Teaching Transparency Activity
✔ Assessment Transparency Activity
HANDS-ON ACTIVITIES
✔ Lab Worksheets for each Student Edition Activity
Teacher Support and Planning
✔ Laboratory Activities
✔ Content Outline for Teaching
✔ Foldables–Reading and Study Skills activity sheet
✔ Spanish Resources
✔ Teacher Guide and Answers
MEETING INDIVIDUAL NEEDS
✔ Directed Reading for Content Mastery
✔ Directed Reading for Content Mastery in Spanish
✔ Reinforcement
✔ Enrichment
✔ Note-taking Worksheets
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Table of Contents
To the Teacher
Reproducible Student Pages
■
iv
Hands-On Activities
MiniLab: Try At Home Calculating Your Work and Power . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
MiniLab: Try At Home Machines Multiplying Force . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Lab Levers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Lab: Model and Invent Work Smarter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Laboratory Activity 1 Balanced Levers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Laboratory Activity 2 Pulleys . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Foldables: Reading and Study Skills . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
■
Meeting Individual Needs
Extension and Intervention
Directed Reading for Content Mastery . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Directed Reading for Content Mastery in Spanish . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Reinforcement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
Enrichment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
Note-taking Worksheet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
■
Assessment
Chapter Review. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
Chapter Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
■
Transparency Activities
Section Focus Transparency Activities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
Teaching Transparency Activity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
Assessment Transparency Activity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
Teacher Support and Planning
Content Outline for Teaching. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . T2
Spanish Resources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . T5
Teacher Guide and Answers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . T10
Additional Assessment Resources available with Glencoe Science:
•
•
•
•
•
•
•
•
•
ExamView ® Pro TestMaker
Assessment Transparencies
Performance Assessment in the Science Classroom
Standardized Test Practice Booklet
MindJogger Videoquizzes
Vocabulary PuzzleMaker at: gpscience.com
Interactive Chalkboard
The Glencoe Science Web site at: gpscience.com
An interactive version of this textbook along with assessment resources are available
online at: mhln.com
iii
Reproducible
Student Pages
Reproducible Student Pages
■
Hands-On Activities
MiniLab: Try at Home Calculating Your Work and Power . . . . . . . . . . 3
MiniLab: Try at Home Machines Multiplying Force . . . . . . . . . . . . . . . 4
Lab Levers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Lab: Model and Invent Work Smarter . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Laboratory Activity 1 Balanced Levers . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Laboratory Activity 2 Pulleys. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Foldables: Reading and Study Skills . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
■
Meeting Individual Needs
Extension and Intervention
Directed Reading for Content Mastery . . . . . . . . . . . . . . . . . . . . . . . . 21
Directed Reading for Content Mastery in Spanish . . . . . . . . . . . . . . . 25
Reinforcement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
Enrichment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
Note-taking Worksheet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
■
Assessment
Chapter Review. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
Chapter Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
■
Transparency Activities
Section Focus Transparency Activities . . . . . . . . . . . . . . . . . . . . . . . . . 46
Teaching Transparency Activity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
Assessment Transparency Activity . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
Work and Machines
1
Hands-On Activities
Hands-On
Activities
2 Work and Machines
Date
Class
Hands-On Activities
Name
Calculating Your Work and Power
Procedure
1. Find a set of stairs that you can safely walk and run up. Measure the vertical
height of the stairs in meters.
2. Record how many seconds it takes you to walk and run up the stairs.
3. Calculate the work you did in walking and running up the stairs using W = F ✕ d.
For force, use your weight in newtons (your weight in pounds ✕ 4.5).
4. Use the formula P = W/t to calculate the power you needed to walk and run
up the stairs.
Data and Observations
Table 1
Height (m)
Walk Time (s)
Run Time (s)
Analysis
1. Is the work you did walking and running the steps the same?
Copyright © Glencoe/McGraw-Hill, a division of the McGraw-Hill Companies, Inc.
2. Which required more power—walking or running up the steps? Why?
Work and Machines
3
Name
Date
Class
Procedure
1. Open a can of food using a manual can opener. WARNING: Do not touch
can opener’s cutting blades or cut edges of the can’s lid.
2. Use a metric ruler to measure the diameter of the cutting blade of the can
opener.
3. Measure the length of the handle you turn.
Data and Observations
1. Diameter of can opener cutting blade:_________________________
2. Length of can opener handle:_________________________
Analysis
1. Compare how difficult it is to open the can using the can opener with how difficult it would
have been to open the can by turning the cutting blade with a smaller handle.
2. Compare the diameter of the cutting blade with the diameter of the circle formed by turning
the can opener’s handle.
3. Infer why a can opener makes it easier to open a metal can.
4 Work and Machines
Copyright © Glencoe/McGraw-Hill, a division of the McGraw-Hill Companies, Inc.
Hands-On Activities
Machines Multiplying Force
Name
Date
Class
Hands-On Activities
Levers
Lab Preview
Directions: Answer these questions before you begin the Lab.
1. Why is it important to repeat steps 5 through 7 with different coins?
2. How is the length of the resistance arm of a lever measured?
Have you ever tried to balance a friend on a seesaw? If your friend was lighter,
you had to move toward the fulcrum. In this lab, you will use the same method
to measure the mass of a coin.
Real-World Question
Materials
stiff cardboard, 3 cm by 30 cm
coins (one quarter, one dime, one nickel)
balance
metric ruler
Goals
■
■
■
Measure the input arm and the output arm
of a lever.
Calculate the ideal mechanical advantage.
Determine the mass of a coin.
Safety Precautions
Procedure
3. Slide the other end of the cardboard strip
over the edge of a table until the strip begins
to tip. Mark a line across the strip at the table
edge and label this line Input.
4. Measure the mass of the strip to the nearest
0.1 g. Write this mass on the input line.
5. Center a dime on the output line. Slide the
cardboard strip until it begins to tip. Mark
the balance line. Label it Fulcrum 1.
6. Measure the lengths of the output and
input arms to the nearest 0.1 cm.
7. Calculate the IMA of the lever. Multiply the
IMA by the mass of the lever to find the
approximate mass of the coin.
8. Repeat steps 5 through 7 with the nickel
and the quarter. Mark the line Fulcrum 2 for
the nickel and Fulcrum 3 for the quarter.
Resistance
fo
r
t
1. Measure the mass of each coin.
2. Mark a line 2 cm from one end of the
paper strip. Label this line Output.
Ef
Copyright © Glencoe/McGraw-Hill, a division of the McGraw-Hill Companies, Inc.
How can a lever be used to measure mass?
Work and Machines
5
Name
Date
Class
(continued)
Coin
Input
Output
IMA
Mass of Coin
Dime
Nickel
Quarter
Conclude and Apply
1. Explain why there might be a difference between the mass of each coin measured by the
balance and the mass measured using the lever.
2. Explain what provides the input and output force for the lever.
3. Explain why the IMA of the lever changes as the mass of the coin changes.
Communicating Your Data
Compare your results with those of other students in your class. For more help, refer to
the Science Skill Handbook.
6 Work and Machines
Copyright © Glencoe/McGraw-Hill, a division of the McGraw-Hill Companies, Inc.
Hands-On Activities
Data and Observations
Name
Date
Class
Model and Invent
Hands-On Activities
Using Simple Machines
Lab Preview
Directions: Answer these questions before you begin the Lab.
1. Give the equation for the IMA of an inclined plane.
2. List several simple machines.
You are the contractor on a one-story building with a large air-conditioner.
The lower the force, the easier the job for your crew. What ways can you
think of to get the air conditioner to the roof?
Real-World Question
How can you minimize the force needed to
lift an object? What machines could you use?
Copyright © Glencoe/McGraw-Hill, a division of the McGraw-Hill Companies, Inc.
Thinking Critically
Consider a fixed pulley with ideal mechanical
advantage (IMA) = 1, a moveable pulley with
IMA = 2, a block and tackle with one fixed
double pulley and one moveable double pulley
with IMA = 4, and an inclined plane with
IMA = slope/height = 4. The latter two
machines may differ in efficiency. How can
you find the efficiency of machines?
Possible Materials
spring scale, 0–10 N range
9.8 N weight (1 kg mass)
two double pulleys
string for pulleys
stand or support for the pulleys
wooden board, 40 cm long
support for board, 10 cm high
Safety Precautions
Goals
■
■
■
Model lifting devices based on a block and
tackle and on an inclined plane.
Calculate the output work that will be
accomplished.
Measure the force needed by each machine
to lift a weight.
■
■
Calculate the input work and efficiency for
each model machine.
Select the best machine for your job based
on force required.
Make the Model
1. Work in teams of at least two. Collect all
the needed equipment.
2. Sketch a model for each lifting machine on a
separate sheet of paper. Model the inclined
plane with a board 40 cm long and raised
10 cm at one end. Include a control in which
the weight is lifted while being suspended
directly from the spring scale.
3. Use the data table in the Data and Observations section to record your information.
4. Is the pulley support high enough that the
block and tackle can lift a weight 10 cm?
5. Obtain your teacher’s approval of your
sketches and data table before proceeding.
Test the Model
1. Tie the weight to the spring scale and
measure the force required to lift it. Record
the effort force in your data table under
Control, along with the 10-cm effort
distance.
2. Assemble the inclined plane so that the
weight can be pulled up the ramp at a constant rate. The 40-cm board should be supported so that one end is 10-cm higher.
Work and Machines
7
Name
Date
Class
(continued)
5. Tie the weight to the single pulley and tie
the spring scale to the string at the top of
the upper double pulley.
6. Measure the force required to lift the
weight with the block and tackle. Record
this effort force.
7. Measure the length of string that must be
pulled to raise the weight 10 cm. Record
this effort distance.
Data and Observations
Control
Inclined
Plane
Block and
Tackle
Ideal Mechanical Advantage, IMA
Input force, Fin, (N)
Input distance, din, (m)
Output force, Fout, (N)
Output distance, dout, (m)
Work in Fe d e, (Joules)
Work out Fr d r, (Joules)
% Efficiency, (Work out / Work in) 100
Analyze Your Data
1. Calculate the output work for all three methods of lifting the 9.8-N weight a distance of 10 cm.
2. Calculate the input work and the efficiency for the control, the inclined plane, and the block
and tackle.
3. Compare the efficiencies of each of the three methods of lifting.
Conclude and Apply
1. Explain how you might improve the efficiency of the machine in each case.
2. Infer what types of situations would require use of a ramp over a pulley to help lift something.
3. Infer which machines would be most likely to be affected by friction.
Communicating Your Data
Make a poster showing how the best machine would be used to lift the air conditioner
to the roof of your building.
8 Work and Machines
Copyright © Glencoe/McGraw-Hill, a division of the McGraw-Hill Companies, Inc.
Hands-On Activities
3. Tie the string to the spring scale and
measure the force required to move the
weight up the ramp at a constant speed.
Record this effort force under Inclined
Plane in your data table. Record 40 cm as
the effort distance for the inclined plane.
4. Assemble the block and tackle using one
fixed double pulley and one moveable
single pulley.
Date
1
Laboratory
Activity
Class
Balanced Levers
In general, a lever is a bar that is free to turn about a pivot point called a fulcrum. When a lever
is balanced horizontally, the following relationship exists:
output force ✕ output arm = input force ✕ input arm
This equation is called the law of the lever.
You can use the principle of balanced levers to construct a mobile. Each of the dowel rods you
will use in constructing your mobile acts as a lever. The point where each string supports a dowel
rod is the fulcrum of the lever. The weights that you hang from the dowel rods to keep the lever in
balance act on the objects as input and output forces. The distances between the objects and the
fulcrum correspond to the input arm and output arm of the balanced lever.
Strategy
You will design and construct a mobile.
You will show that each lever in your mobile obeys the law of the lever.
Materials
string
meterstick
4 wooden dowel rods (one 50 cm long, the others at various shorter lengths)
various objects of different weights (paper clips, keys, etc.)
metric spring scale (calibrated in newtons)
Copyright © Glencoe/McGraw-Hill, a division of the McGraw-Hill Companies, Inc.
Procedure
1. Tie a piece of string near the center of the
50 cm dowel. Anchor the other end of the
string to the tabletop or ceiling, if possible.
Allow room below this dowel to add
objects to the mobile.
2. Weigh each object that you plan to use in
constructing your mobile. Record the
weights of the objects in Table 1. Be sure to
include the smaller dowel rods when you
weigh the objects.
3. Use the string and remaining rods to
construct the mobile. You may use any
design. However, the main lever (50-cm rod)
and any other dowels you use must be
balanced horizontally. See Figure 1.
4. When you are finished, measure the distance in mm from each hanging object to
the fulcrum of each lever. When recording
these distances in Table 2, choose one distance on the balanced lever as the output
arm and the other as the input arm. Thus,
the weight of the object hanging from the
output arm is the output force. The weight
of the object hanging from the input arm
is the input force.
Figure 1
Work and Machines
9
Hands-On Activities
Name
Name
Date
Class
Laboratory Activity 1 (continued)
For each lever, calculate the product of the output force and the output arm and the product of
the input force and the input arm. Record your calculations in Table 2. Use your calculations to
support the law of the lever.
Table 1
Object
Weight (N)
Object
Weight (N)
Table 2
Lever
Input
arm (mm)
Input
force (N)
Product
(N mm)
Output
arm (mm)
Output
force (N)
Product
(N mm)
A
B
C
D
Questions and Conclusions
1. A 25-N weight hangs 10 cm to the left of the fulcrum of a lever. A 15-N weight hangs 12 cm to
the right of the fulcrum. Is the lever balanced? How do you know?
2. How does the length of string used to hang the objects affect their position on the lever?
10 Work and Machines
Copyright © Glencoe/McGraw-Hill, a division of the McGraw-Hill Companies, Inc.
Hands-On Activities
Data and Observations
Name
Date
Class
Hands-On Activities
Laboratory Activity 1 (continued)
3. When is an equal arm balance an example of a balanced lever?
4. For the balanced levers shown in Figure 2, use the law of the levers to fill in the missing data
for a and b.
Figure 2
4 cm
6 cm
a.
9N
8 cm
2 cm
2 cm
b.
15 N
Copyright © Glencoe/McGraw-Hill, a division of the McGraw-Hill Companies, Inc.
Strategy Check
Can you design and construct a working mobile?
Can you show that each lever in your mobile obeys the law of the lever?
Work and Machines
11
Date
2
Laboratory
Activity
Class
Pulleys
If you have ever raised or lowered a flag or slatted blinds, you used a simple machine called a
pulley. As you recall, simple machines can change direction of a force and multiply either the size
of the effort force or the distance that the resistance force moves.
A single fixed pulley is a pulley that can’t move up and down. As you can see in
Figure 1, a fixed pulley is actually a lever in the form of a circle. Can you locate the effort
arm and the resistance arm in a single fixed pulley?
Figure 1
Effort Force
Resistance Force
Fulcrum
Resistance Arm
Fulcrum
Effort Arm
Resistance Force
Effort Force
Copyright © Glencoe/McGraw-Hill, a division of the McGraw-Hill Companies, Inc.
A series of pulleys is called a block and tackle. You may have seen a block and tackle in an auto
repair shop. It sometimes is used to lift car engines. Look at the block and tackle shown in Figure 2.
Can you locate a single fixed pulley in the block and tackle?
Figure 2
Effort force
Resistance force
Strategy
You will perform work using a single fixed
pulley.
You will construct a block and tackle and per
form work with it.
You will compare the properties of a single
fixed pulley and a block and tackle.
Materials
utility clamp
ring stand
plastic-coated wire ties, 10 cm and 30 cm long
2 pulleys
meterstick
1-m length of cotton string
masking tape
metric spring scale
0.5-kg and 1-kg standard masses
Work and Machines
13
Hands-On Activities
Name
Name
Date
Class
Laboratory Activity 2 (continued)
Part A—Single Fixed Pulley
1. Attach the utility clamp to the top of a ring
stand. Use the short plastic-coated wire tie
to attach one of the pulleys to the utility
clamp. Attach a meterstick to the ring
stand with tape. See Figure 3.
2. Tie a small loop at each end of the 1-m
length of string. Thread the string over the
pulley.
3. Tightly wrap the second plastic-coated wire
tie around the 0.5 kg mass. Attach the mass
to the hook of the spring scale with the wire
tie. Measure the weight of the 0.5 kg mass.
Record this value as the resistance force in
Table 1.
4. Remove the mass from the spring scale. Use
the wire tie to attach the mass to one loop
of the pulley string. Attach the hook of the
spring scale to the loop at the opposite end
of the string.
Part B—Block and Tackle
1. Attach a second pulley to one of the loops
of the pulley string. Thread the loop at the
opposite end of the pulley string under the
second pulley as shown in Figure 4.
2. Adjust the height of the utility clamp so
the pulley can move upward at least 25 cm
from the table top.
Figure 4
Meterstick
Meterstick
Spring scale
Utility clamp
Wire tie
Pulley
Ring stand
14 Work and Machines
0.5-kg mass
Copyright © Glencoe/McGraw-Hill, a division of the McGraw-Hill Companies, Inc.
Figure 3
5. Slowly pull straight down on the spring
scale to raise the mass. Measure the force
needed to raise the mass 15 cm. Record this
value as the effort force in Table 1.
6. Lower the mass to the table top. As you again
pull down on the spring scale, measure the
distance the spring scale moves as you raise
the mass a distance of 15 cm. Record this
value as the effort distance in Table 1.
7. Remove the 0.5 kg mass and the spring
scale from the string.
8. Repeat steps 4–7 for the 1 kg mass and the
combined 0.5 kg and the 1 kg masses.
Block and tackle
Hands-On Activities
Procedure
Name
Date
Class
3. Wrap the plastic wire tie securely around
the 0.5 kg mass. Use the spring scale to
measure its weight. Record this value as the
resistance force in Table 2. Attach the mass
to the second pulley.
4. Attach the spring scale to the loop on the
free end of the string.
5. Slowly pull straight up on the spring scale
to raise the mass as shown in Figure 4.
Measure the force needed to raise the mass
15 cm. Record this value as the effort
distance in Table 2.
6. Lower the mass to the table top. As you again
pull up on the spring scale, measure the distance the spring scale moves as you raise the
mass a distance of 15 cm. Record this value
as the effort distance in Table 2.
7. Remove the 0.5 kg mass from the pulley
and the spring scale from the string.
8. Repeat steps 4–7 for the 1 kg mass and the
combined 0.5 kg and 1 kg masses.
Copyright © Glencoe/McGraw-Hill, a division of the McGraw-Hill Companies, Inc.
Data and Observations
1. Use Graph 1 to construct a bar graph comparing the effort force of the single
fixed pulley, the effort force of the block and tackle, and the resistance force
for each of the three masses. Plot the value of the masses on the x axis and
the force on the y axis. Label the x axis Mass (kg) and the y axis Force (N).
Clearly label the bars that represent the values of the effort force of the single
fixed pulley, the effort force of the block and tackle, and the resistance force.
2. Use Graph 2 to construct a bar graph comparing the effort distance of the
single fixed pulley, the effort distance of the block and tackle, and the
resistance distance for each of the three masses. Plot the value of the masses
on the x axis and the distance on the y axis. Label the x axis Mass (kg) and
the y axis Distance (cm). Clearly label the bars that represent the values of
the effort distance of the single fixed pulley, the effort distance of the block
and tackle, and the resistance distance.
3. Work input is the work done by you. Work input can be calculated using the
following equation.
Work input = Effort force ✕ Effort distance
If the force is measured in newtons (N) and the distance is measured in meters
(m), work will be expressed in joules (J). Calculate the work input for the
pulley and the block and tackle for each mass. Record the values in Table 3.
4. Work output is the work done by the machine. Work output can be calculated using the following equation.
Work output = Resistance force ✕ Resistance distance
If the force is measured in newtons (N) and the distance is measured in meters
(m), work will be expressed in joules (J). Calculate the work output for the
pulley and the block and tackle for each mass. Record the values in Table 3.
5. The efficiency of a machine is a measure of how the work output of a
machine compares with the work input. The efficiency of a machine can be
calculated using the following equation.
Efficiency = Work output/Work input ✕ 100%
Use this equation to calculate the efficiency of the single fixed pulley and the
efficiency of the block and tackle in raising each mass. Record these values
in Table 4.
Work and Machines
15
Hands-On Activities
Laboratory Activity 2 (continued)
Name
Date
Class
Laboratory Activity 2 (continued)
Mass (kg)
Resistance
force (N)
Effort
force (N)
Resistance
distance (cm)
0.5
15.0
1.0
15.0
1.5
15.0
Effort
distance (cm)
Table 2
Mass (kg)
Resistance
force (N)
Effort
force (N)
Resistance
distance (cm)
0.5
15.0
1.0
15.0
1.5
15.0
Effort
distance (cm)
Table 3
Single fixed pulley
Block and tackle
Mass (kg)
Work input (J)
Work output (J)
Work input (J)
0.5
1.0
1.5
Table 4
Efficiency (%)
Mass (kg)
Single fixed pulley
0.5
1.0
1.5
16 Work and Machines
Block and tackle
Work output (J)
Copyright © Glencoe/McGraw-Hill, a division of the McGraw-Hill Companies, Inc.
Hands-On Activities
Table 1
Copyright © Glencoe/McGraw-Hill, a division of the McGraw-Hill Companies, Inc.
Date
Graph 1
Hands-On Activities
Name
Class
Laboratory Activity 2 (continued)
Graph 2
Work and Machines
17
Name
Date
Class
Laboratory Activity 2 (continued)
1. The effort distance is very much greater than the resistance distance in which machines(s)?
2. The effort force is very much less than the resistance force in which machine(s)?
3. In which machine(s) is the work output greater than the work input?
4. Explain how using a single fixed pulley to raise a flag makes the task easier.
5. Explain how using a block and tackle to lift a car engine makes the task easier.
6. Compare the efficiencies of the single fixed pulley and the block and tackle. Why would you
expect the block and tackle to be less efficient than the single fixed pulley?
Strategy Check
Can you perform work with a single fixed pulley and with a block and tackle?
Can you explain the differences between a single fixed pulley and a block and tackle?
18 Work and Machines
Copyright © Glencoe/McGraw-Hill, a division of the McGraw-Hill Companies, Inc.
Hands-On Activities
Questions and Conclusions
Name
Date
Class
Hands-On Activities
Work and Machines
Directions: Use this page to label your Foldable at the beginning of the chapter.
Work with Machines
Work without Machines
carrying a heavy sack of mulch to the backyard
Copyright © Glencoe/McGraw-Hill, a division of the McGraw-Hill Companies, Inc.
carrying books up the stairs
lifting a box
throwing a ball
walking 3 km
Work and Machines
19
Meeting Individual Needs
Meeting Individual
Needs
20 Work and Machines
Name
Date
Directed Reading for
Content Mastery
Class
Overview
Work and Machines
Directions: Complete the concept map using the terms in the list below.
multiply
wedge
wheel and axle
force
inclined plane
pulley
distance
Meeting Individual Needs
machines
lever
screw
Work
equals
1.
can be made
easier by using
3.
simple machines
such as
times
2.
can be done by
that
5.
Copyright © Glencoe/McGraw-Hill, a division of the McGraw-Hill Companies, Inc.
4.
6.
force
7.
8.
9.
10.
Work and Machines
21
Name
Date
Directed Reading for
Content Mastery
Section 1
Section 2
Class
■
■
Work
Using Machines
Directions: In the blank, write the term from the list below that correctly completes each statement about the
equations given. Terms may be used more than once.
output paperwork
input work
time
distance
energy
power
Meeting Individual Needs
1. In the equation W = F ✕ d
force
height of slope
3. In the equation P = W/t
a. W stands for _______________.
a. P stands for ________________.
b. F stands for ________________.
b. W stands for ________________.
c. d stands for ________________.
c. t stands for ________________.
2. In the equation Win = Wout
4. In the equation P = E/t
a. Win stands for ______________.
a. E stands for ________________.
b. Wout stands for _____________.
b. t stands for ________________.
Directions: In the words below, code letters have been substituted for letters of the alphabet. Use the following
key to decode the words. In the key, the code letters are shown directly above the alphabet letter each stands for.
Write the correct words on the lines provided.
A B C D E F G H J K L N O R T U W X Y Z
r w h i c l o s m v d u t g a f n e j y
Prying into things
5. XWXARZ
6. YGNFX
7. XUUGAO UGAEX
8. AXHDHOTWEX UGAEX
9. JXECTWDETF TLKTWOTRX
10. LDAXEOD GW
11. WXB O GW
22 Work and Machines
Copyright © Glencoe/McGraw-Hill, a division of the McGraw-Hill Companies, Inc.
work
Name
Date
Directed Reading for
Content Mastery
Section 3
Class
■
Simple Machines
1. CEFRO
push or pull
2. HELEW
used with an axle
3. FCYENFCIEI
measure of how much
work put into a machine is
changed to useful work
put out by the machine
4. KROW
exertion of a force
through a distance
5. PODNUCMO
type of machine made
up of two or more simple
machines
Meeting Individual Needs
Directions: Unscramble the five terms related to machines. The hints beside each scrambled term will help you.
Write each unscrambled term in the boxes below. Use only one letter in each box. Use the circled letters to find the
missing term in the equation.
Copyright © Glencoe/McGraw-Hill, a division of the McGraw-Hill Companies, Inc.
Equation: _________________________ = work/time
6
Directions: Solve the puzzle by writing
the term that best fits each definition. You
will find another term spelled vertically in
the black box.
7
8
Definitions
6. An automobile is this
kind of machine.
10
7. distance from center of
a circle to its edge
11
8. fixed point on which a
lever rotates
9. A measure of the amount
a machine multiplies a
force is its ______
advantage.
10. A fixed pulley changes the______
of a force.
11. a force that opposes motion
9
12
13
12. simple machines made up of two
inclined planes
13. inclined plane wrapped around a
cylindrical post
Work and Machines
23
Name
Date
Directed Reading for
Content Mastery
Class
Key Terms
Work and Machines
Directions: Unscramble the terms in italics to complete the sentences below. Write the terms on the lines provided.
1. The force applied by a machine to overcome another
force is the stirnecesa force.
2. The force that is applied to the machine is the oftref
force.
Meeting Individual Needs
3. When a force is applied through a distance, krow is
done.
4. A device that makes work easier is a himcaen.
5. The work done to a machine is iutnp work.
6. A machine in which input work is equal to output
work is an ilead machine.
7. A device that does work with only one movement is a
plimes machine.
8. The number of times a machine multiplies the effort
force is the leahincamc gavetadna.
10. A machine makes work easier by changing the size or
direction of the ceorf exerted on an object.
Directions: In the space at the left, write the term that best completes each statement. Use the terms listed below.
block and tackle
pulley
screw
inclined planes
wheel and axle
11. An inclined plane wrapped around a cylindrical post
is a ______.
12. A doorknob is an example of a ______.
13. A grooved wheel with a rope or a chain running
along the groove is a ______.
14. Screws and wedges are types of ______.
15. A system of pulleys is called a ______.
24 Work and Machines
Copyright © Glencoe/McGraw-Hill, a division of the McGraw-Hill Companies, Inc.
9. The work done by a machine is the touupt work.
Nombre
Fecha
Lectura dirigida para
Dominio del contenido
Clase
Sinopsis
Trabajo y máquinas
Instrucciones: Complete el mapa conceptual usando los siguientes términos.
multiplica
cuña
rueda y eje
fuerza
plan inclinado
polea
distancia
Satisface las necesidades individuales
máquinas
palanca
tornillo
El trabajo
es igual a
1.
puede facilitarse
usando
3.
máquinas simples
como por ejemplo,
por
2.
se puede realizar con
que
5.
4.
Copyright © Glencoe/McGraw-Hill, a division of the McGraw-Hill Companies, Inc.
6.
la fuerza
7.
8.
9.
10.
Trabajo y máquinas
25
Nombre
Fecha
Lectura dirigida para
Dominio del contenido
Sección 1
Sección 2
Clase
■
■
Trabajo
Usa máquinas
Instrucciones: Escribe en los espacios en blanco el término de lista que completa correctamente cada oración
sobre la ecuación dada. Puedes usar los términos más de una vez.
trabajo producido
tiempo
distancia
potencia
Satisface las necesidades individuales
1. En la ecuación W = F × d
a. W simboliza _______________.
b. F simboliza ________________.
c. d simboliza ________________.
2. En la ecuación Win = Wout
a. Win simboliza ______________.
b. Wout simboliza _____________.
trabajo invertido
energía
fuerza
3. En la ecuación P = W/t
a. P simboliza ________________.
b. W simboliza ________________.
c. t simboliza ________________.
4. En la ecuación P = E/t
a. E simboliza ________________.
b. t simboliza ________________.
Instrucciones: En las siguientes palabras, se han sustituido las letras del alfabeto por letras en código. Usa la
clave para descodificar las palabras. En la clave, las letras del código se muestran directamente encima de la letra
del alfabeto que cada una representa. Escribe la palabra correcta en las líneas.
A B C D E F G H I J K L N Ñ O Ö Q R S T U Ü V W X Y Z
r w h i c l o s z m v d u ü t ú ó g í a f q á n e j y
¡Encuéntralas!
5. XWXARST
6. YGNFX
7. UNXAIT LX XHUNXAIG
8. UNXAIT LX AXHDHOXWEDT
9. KXWOTYT JXEVWDET
10. LDAXEEDQW
11. WXB O GW
26 Trabajo y máquinas
Copyright © Glencoe/McGraw-Hill, a division of the McGraw-Hill Companies, Inc.
trabajo
Nombre
Fecha
Lectura dirigida para
Clase
Sección 3
Máquinas
simples
■
Dominio del contenido
1. ZERUFA
empujón o halón
2. DEURA
se usa con un eje
3. CAEIFICENI
medida de la cantidad de
trabajo que se pone en una
máquina y la máquina
convierte en trabajo útil
4. BJARTOA
fuerza hecha a través de
una distancia
5. MTASCEUOP
tipo de máquina formada
por de dos o más máquinas
simples
Satisface las necesidades individuales
Instrucciones: Ordena las letras para descifrar cinco términos relacionados con las máquinas. Las pistas que
aparecen a la par de cada término te ayudarán. Escribe cada término en los cuadros. Usa solamente una letra por
cuadro. Usa las letras en los círculos para encontrar el término que hace falta en la ecuación.
Copyright © Glencoe/McGraw-Hill, a division of the McGraw-Hill Companies, Inc.
Ecuación: _________________________ = trabajo/tiempo
Instrucciones: Resuelve el crucigrama
escribiendo el mejor término para cada
definición. Encontrarás otro término en la
caja vertical oscura.
6
7
Definiciones
12. Un auto es este tipo de
máquina.
7. Distancia desde el
centro de un círcu10
lo hasta el borde
8. Punto fijo sobre el que
rota una palanca
6. Medida de cuánto una
12
máquina multiplica una
fuerza es su ventaja ______.
10. Una polea fija cambia el(la) ______
de la fuerza.
9. Fuerza que se opone al movimiento
Q
8
9
11
11. Máquina simple compuesta de dos
planos inclinados
Trabajo y máquinas
27
Nombre
Fecha
Lectura dirigida para
Dominio del contenido
Clase
Términos claves
Trabajo y máquinas
Instrucciones: Reordena las letras de los términos en bastardilla para completar cada oración. Escribe los términos
en las líneas.
1. La fuerza aplacada por una máquina para sobreponerse a otra fuerza es la fuerza de cairissteen.
Satisface las necesidades individuales
2. La fuerza que se aplica a la máquina es fuerza de
efouzesr.
3. Se hace bjataro cuando se aplica una fuerza a través
de una distancia.
4. Aparato que facilita el trabajo es una qiuaman.
5. El trabajo que se le hace a la máquina es trabajo de
datraen.
6. Máquina en que el trabajo de entrada es igual al trabajo de salida es una máquina ilead.
8. El número de veces que una máquina multiplica la
fuerza de esfuerzo es ella aenjatv cianmaec.
9. El trabajo que la máquina hace es jobatra de idsala.
10. Una máquina facilita el trabajo cambiando el tamaño
o la dirección de la urefaz que se aplica a un objeto.
Instrucciones: En el espacio a la izquierda de cada oración, escribe el término que completa mejor cada afirmación.
aparejo de poleas
polea
tornillo
planos inclinados
rueda y eje
11. Un plano inclinado enrollado alrededor de una varilla cilíndrica es un(a) ______.
12. La perilla de una puerta ejemplifica un(a) ______.
13. Una rueda con un canal que tiene una cuerda o
cadena que corre a lo largo del canal es un(a) ______.
14. Los tornillos y las cuñas son tipos de ______.
15. Un sistema de poleas se llama un(a) ______.
28 Trabajo y máquinas
Copyright © Glencoe/McGraw-Hill, a division of the McGraw-Hill Companies, Inc.
7. Un aparato que hace trabajo con un solo movimiento
es un máquina plimes.
Name
1
Date
Reinforcement
Class
Work
Directions: Use the formula work = force ✕ distance to calculate the answers to each of the following questions.
Meeting Individual Needs
1. A box is pushed 40 m by a mover. The amount of work done was 2,240 J. How much force was
exerted on the box?
Copyright © Glencoe/McGraw-Hill, a division of the McGraw-Hill Companies, Inc.
2. A person expended 500 newtons to move a full wheelbarrow 30 meters. How much work
was done?
Directions: Use the formula power = work/time to calculate the power required in each of the following.
3. A weightlifter lifts a 1,250-N barbell 2 m in 3 s. How much power was used to lift the barbell?
4. A crane lifts a 35,000-N steel girder a distance of 25 m in 45 s. How much power did the crane
require to lift the girder? Write your answers in kilowatts.
Work and Machines
29
Name
2
Date
Reinforcement
Class
Using Machines
Directions: In the space provided, define and express the term or equation for each of the following.
1. effort force
2. resistance force
4. efficiency
Directions: Use the information above to solve the following problem.
5. A carpenter uses a crowbar to remove the top of a box. The top has a resistance of 500 N. The
carpenter applies an effort force of 250 N. What is the mechanical advantage of the crowbar?
Directions: Answer the following questions with complete sentences.
6. What are two ways that machines make work easier?
7. How does a crowbar used to remove the top of a box change the direction of the force?
8. What is ideal mechanical advantage?
30 Work and Machines
Copyright © Glencoe/McGraw-Hill, a division of the McGraw-Hill Companies, Inc.
Meeting Individual Needs
3. mechanical advantage
Name
Date
3
Reinforcement
Class
Simple Machines
Directions: Match each simple machine in Column II to its description in Column I. Write the letter of the simple
machine in the blank at the left.
Column I
1. bar that is free to pivot about a fixed point
a. wheel and axle
2. an inclined plane with one or two sloping slides
b. inclined plane
3. grooved wheel with a rope running along the groove
c. gear
4. two wheels of different sizes that rotate together
5. sloping surface used to raise objects
d. lever
e. wedge
6. two wheels of different sizes with interlocking teeth along
their circumferences
f. pulley
7. inclined plane wrapped in a spiral around a cylindrical post
g. screw
Directions: Classify each type of simple machine as either a lever or an inclined plane by writing its name in the
proper column of the table.
Copyright © Glencoe/McGraw-Hill, a division of the McGraw-Hill Companies, Inc.
8. Levers
9. Inclined planes
Directions: Calculate the ideal mechanical advantage for each of the following.
10. A mover uses a ramp to push a stereo into the moving van. The ramp is 3 meters long and
1.5 meters high. What is the ideal mechanical advantage of this ramp?
11. A painter uses a fixed pulley to raise a 1-kg can of paint a distance of 10 m.
12. A screwdriver with a 1-cm shaft and a 4-cm handle is used to tighten a screw.
Work and Machines
31
Meeting Individual Needs
Column II
Name
1
Date
Enrichment
Class
Calculating Work
Directions: Solve the following problems.
1. A box weighing 354 N is pushed up an inclined plane that is 3m long. A force of 275 N is
required, including friction.
ete
3m
rs
N
275
354 N
a. What is the work done to slide the box?
b. How much work is done if the box is lifted 1 m instead?
c. Which method of lifting the box requires more work?
d. Which method of lifting the box would be easier?
2. How much power is generated if a person applies 200 N of force to move a bicycle 10 m in 5 s?
3. A 700-watt gasoline engine and a 300-watt electric motor both do 3 J of work. Which
machine can do the work faster? Explain your answer.
4. In the English system, the unit of power is the horsepower. It is based on the amount of work
the average horse can do. (1 horsepower = 746 watts).
a. If a car engine is rated at 125 horsepower, how many watts of power does it produce?
b. If a lawnmower engine is rated at 4 horsepower, how many watts of power is that?
32 Work and Machines
Copyright © Glencoe/McGraw-Hill, a division of the McGraw-Hill Companies, Inc.
Meeting Individual Needs
1 meter
Name
Plotting Force and
Displacement
Another way of analyzing the work done by a force is to do a forcedisplacement graph. The graph to the right is a plot of force vs.
displacement for a 30 N box being lifted 2.0 m. The shaded area under
the graph (Figure 1) equals the work input. (Win = Fe ✕ de = 30N ✕
2.0 m = 60 J) Since no machine was used to lift the box, the graph of
work output would be the same.
(Wout = Fr ✕ d r = 30N ✕ 2.0 m = 60 J)
Figure 1
40
30
20
10
Directions: Solve the following problems using force-displacement graphs.
1.0
2.0
3.0
Displacement (m)
Figure 3
Figure 2
40
40
30
30
Force (N)
Force (N)
2. Draw a force-displacement graph
in Figure 3 showing the work
input and the work output for the
same box if the books are lifted by a
pulley system with an IMA of 2.
0
0
20
20
10
10
0
0
0
1.0
2.0
0
3.0
Displacement (m)
3. A force of 70 N is required to remove a bottle cap
without using an opener. Draw a force-displacement
graph in Figure 4 for the work output when the
bottle cap is moved 1 cm.
4. Draw a force-displacement graph in Figure 4 for work
input on the same bottle cap being removed by an
opener resulting in an IMA of 3.5.
1.0
2.0
3.0
Displacement (m)
Figure 4
70
60
50
Force (N)
Copyright © Glencoe/McGraw-Hill, a division of the McGraw-Hill Companies, Inc.
1. Draw a force-displacement graph
in Figure 2 showing the work input
and the work output when a box of
books that needs a force of 40 N is
lifted 1.5 m.
40
30
20
10
0
0
0.01
0.02
0.03
0.04
Displacement (m)
Work and Machines
33
Meeting Individual Needs
Enrichment
Class
Force (N)
2
Date
Name
Enrichment
Class
The Bicycle
Meeting Individual Needs
A machine multiplies either speed or force
but never both at the same time. When you
ride a bicycle, the gears increase your force or
decrease your force. This change in force
results in slower speeds or faster speeds.
For a bicycle, the mechanical advantage
(IMA) is the number of times the applied force
is multiplied. The speed average (ISA) is the
number of times that the machine multiplies
the speed. If a bicycle multiplies the force of
your legs by two, the speed is divided by two.
2. Obtain a ten-speed bike. Count the teeth in
the front and rear gears in speeds 1, 5, 6, and
10. Record your data in the table and calculate the ISA and the IMA for each speed.
10-Speed Bike
Speed
Front
Rear
ISA
IMA
1
5
6
Procedure
1. Use the figure below to estimate the number
of teeth shown in the two gears. Use the following formulas to find IMA and ISA for
the gears shown.
ISA = number front teeth/number rear
teeth
IMA = number rear teeth/number front
teeth
10
3. Obtain a mountain bike and count the
teeth in the front and rear gears in speeds
1, 6, 13, and 18. Record your data in the
table and calculate the ISA and the IMA.
Mountain Bike
Speed
Front
Rear
ISA
IMA
1
6
13
Rear gears
Front gears
18
Questions
1. What gear combination produces the greatest ideal mechanical advantage in the ten-speed
bike? The mountain bike?
2. What gear combination produces the greatest speed advantage in the ten-speed bike? The
mountain bike?
3. Explain why the gear combinations in a ten-speed bike are made for maximum speed advantage,
while the combinations in a mountain bike are made for maximum mechanical advantage?
34 Work and Machines
Copyright © Glencoe/McGraw-Hill, a division of the McGraw-Hill Companies, Inc.
3
Date
Name
Date
Note-taking
Worksheet
Section 1
Class
Work and Machines
Work
A. ______________—transfer of energy that occurs when a force makes an object move
1. For work to occur, an object must ______________.
B. Work and energy are related, since energy is always _____________________ from the object
doing the work to the object on which the work is done.
C. Work is done on an object only when a _______________ is being applied to the object and
the object moves.
D. Calculating work—work equals force (in newtons) times __________________
E. _______________—amount of work done in a certain amount of time; rate at which work is
done
1. ___________________________—power equals work divided by time.
2. Power is measured in _______________ (W).
Copyright © Glencoe/McGraw-Hill, a division of the McGraw-Hill Companies, Inc.
3. Since work and energy are _________________, power also can be calculated—power
equals energy divided by time.
Section 2
Using Machines
A. Device that makes doing work easier is a _________________.
B. Machines __________________ applied force and/or ________________ direction of applied
force to make work easier.
1. Same amount of work can be done by applying a small force over a long distance as can be
done applying a large force over a short distance, since work equals _______________
times __________________.
2. Increasing __________________ reduces the amount of force needed to do the work.
3. Some machines change the ___________________ of the applied force to do the work.
C. Machines help move things that ________________ being moved.
1. Force applied to machine is ______________________.
2. __________________________—force applied by machine to overcome resistance
Work and Machines
35
Meeting Individual Needs
2. The motion of the object must be in the ________________________ as the applied force
on the object.
Name
Date
Class
Note-taking Worksheet (continued)
3. Amount of energy the machine transfers to the object cannot be _________________ than
the amount of energy transferred to the machine.
a. Some energy transferred is changed to ______________ due to friction.
b. An ideal machine with no __________________ would have the same input work and
output work.
D. ______________________________ (MA) is the number of times a machine multiplies the
effort force. It is calculated by MA equals resistance force divided by effort force.
1. _____________________ efficiency—efficiency equals (output work divided by input work)
times 100%.
2. Efficiency of a machine is always ______________ than 100%.
3. ____________________ can make machines more efficient by reducing friction.
Section 3
Simple Machines
A. A machine that does work with only one movement is a ________________________.
B. _______________—bar that is free to pivot about a fixed point called the fulcrum
1. ________________ arm is part of the lever on which effort force is applied.
2. ____________________ arm is part of the lever that exerts the resistance force.
3. Three classes of levers based on ___________________ of effort force, resistance force, and
fulcrum
a. _____________________ lever—fulcrum is located between the effort and resistance
forces; multiplies and changes direction of force
b. ______________________ lever—resistance force is located between the effort force
and fulcrum; always multiplies force
c. _____________________ lever—effort force is between the resistance force and fulcrum;
doesn’t multiply force but does increase distance over which force is applied
4. Calculating ideal mechanical advantage (IMA) of a lever—IMA equals length of
________________ arm divided by length of output arm.
36 Work and Machines
Copyright © Glencoe/McGraw-Hill, a division of the McGraw-Hill Companies, Inc.
Meeting Individual Needs
E. ____________________—measure of how much of the work put into a machine is changed
into useful output work by the machine
Name
Date
Class
Note-taking Worksheet (continued)
C. Grooved wheel with a rope, simple chain, or cable running along the groove is a
________________, which is a modified first-class lever.
1. A _______________ pulley is attached to something that doesn’t move; force is not multiplied
but direction is changed; IMA = 1.
2. A _________________ pulley has one end of the rope fixed and the wheel free to move;
multiplies force; IMA = 2.
D. ________________________—machine with two wheels of different sizes rotating together;
modified lever form
1. IMA = radius of wheel _________________ by the radius of axle
2. _______________ are a modified form of the wheel and axle.
E. ________________________—sloping surface that reduces the amount of force required to
do work
1. IMA = length of slope (effort distance) _________________ by height of slope (resistance
distance)
Copyright © Glencoe/McGraw-Hill, a division of the McGraw-Hill Companies, Inc.
2. _______________ is required if a ramp is longer and less steep.
F. _______________—inclined plane wrapped in a spiral around a cylindrical post
G. Inclined plane with one or two sloping sides is a _______________.
H. __________________________—uses a combination of two or more simple machines
Work and Machines
37
Meeting Individual Needs
3. __________________________—system of pulleys consisting of fixed and movable pulleys;
IMA = number of ropes supporting resistance weight
Assessment
Assessment
38 Work and Machines
Name
Date
Chapter
Review
Class
Work and Machines
Part A. Vocabulary Review
Directions: Identify each statement as true or false. Replace the italicized term in false statements with the
term that makes them correct.
1. A device that does work with only one movement is a compound machine.
2. The number of times a machine multiplies the effort force is the resistance force
of the machine.
3. A grooved wheel with a rope or chain running through the groove is a pulley.
4. A wheel with teeth along its circumference is a pulley.
5. A sloping surface used to raise objects is a wedge.
7. A wheel and axle is a simple machine consisting of two wheels of different sizes that
rotate together.
Assessment
Copyright © Glencoe/McGraw-Hill, a division of the McGraw-Hill Companies, Inc.
6. A screw is an inclined plane wrapped in a spiral around a cylindrical post.
8. An inclined plane with two or more sloping sides is a screw.
9. The mechanical advantage of a fixed pulley is always two.
10. A machine made up of two or more simple machines is a(n) ideal machine.
11. The mechanical advantage of a block and tackle is equal to the number of ropes used
to raise the object.
12. Power is the rate at which work is done.
13. A measure of how well a machine operates is its efficiency.
Work and Machines
39
Name
Date
Class
Chapter Review (continued)
Part B. Concept Review
Directions: In the blank at the left, write the name of the simple machine represented by each example.
1. staircase
5. knife
2. spiral
staircase
6. screwdriver
7. block and
tackle
3. crowbar
4. bicycle
pedals
8. ramp
Directions: In the spaces provided, label the following diagram by writing the letter of the term that correctly
identifies each part.
a. fulcrum
b. output arm
c. input arm
d. resistance force
e. effort force
12.
9.
10.
11.
Assessment
Directions: Calculate the ideal mechanical advantage for each of the machines shown. Write your answers in
the spaces provided.
14.
N
15 0 N
6
rce
o
F
15.
16.
2
1.5 m
1
r = 9 cm
r = 0.6 cm
14.
15.
16.
Directions: Answer the following question using complete sentences.
17. What is the difference between ideal mechanical advantage and actual mechanical advantage?
40 Work and Machines
Copyright © Glencoe/McGraw-Hill, a division of the McGraw-Hill Companies, Inc.
13.
Transparency Activities
Transparency
Activities
Work and Machines
45
Name
1
Date
Section Focus
Transparency Activity
Class
Onward and Upward
Transparency Activities
1. Compare the effort exerted by a backpacker moving over level
ground to that exerted by a backpacker moving uphill.
2. How do you think the weight of the backpack affects the amount
of force needed to move it?
46 Work and Machines
Copyright © Glencoe/McGraw-Hill, a division of the McGraw-Hill Companies, Inc.
Backpacking is a lot of fun, but it also can be a lot of work. Whether
hoisting the pack onto your back to start the hike or trudging up a
long hill, you’ll need to exert a good deal of effort to get to the next
camp.
Name
2
Date
Section Focus
Transparency Activity
Class
A Quiet Glide
1. How is a person paddling a canoe doing work?
2. If the paddle broke, would it be easier or more difficult to move
the canoe? Explain.
Transparency Activities
Copyright © Glencoe/McGraw-Hill, a division of the McGraw-Hill Companies, Inc.
For some people, paddling a canoe is a pleasant diversion. For
others, it’s work. Out on a lake, the paddle is a big help in moving
the canoe. It might even make work fun!
3. How does the shape of the canoe make paddling easier?
Work and Machines
47
Name
3
Date
Section Focus
Transparency Activity
Class
Moving Day
Transparency Activities
1. What do you see in this picture that makes it easier for the mover
to do work?
2. How do the ramp and dolly make work easier?
48 Work and Machines
Copyright © Glencoe/McGraw-Hill, a division of the McGraw-Hill Companies, Inc.
Moving can be a chore. Packing boxes, moving them, then unpacking
everything can be hard work. But machines can help. Some machines
are simple, while others can be very complicated. This mover uses a
selection of machines to help make moving day much easier.
3
Date
Teaching Transparency
Activity
Transparency Activities
Copyright © Glencoe/McGraw-Hill, a division of the McGraw-Hill Companies, Inc.
Name
Class
Simple Machines
Output ar
arm
Input ar
arm
Work and Machines
49
Name
Teaching Transparency Activity
Date
Class
(continued)
1. What is a simple machine?
2. List the six types of simple machines.
3. What is a compound machine?
4. On the transparency, which two simple machines are forms of the inclined plane.
5. Is the lever on the transparency a first-class, second-class, or third-class lever?
7. What kind of pulley is illustrated on the transparency? Does it multiply force?
Transparency Activities
50 Work and Machines
Copyright © Glencoe/McGraw-Hill, a division of the McGraw-Hill Companies, Inc.
6. What type of lever cannot multiply force?
Name
Date
Class
Work and Machines
Assessment
Transparency Activity
Directions: Carefully review the table and the diagram and answer the following questions.
Position
Input
distance
Output
distance
Effort
force
A
40 cm
40 cm
20 N
B
40 cm
20 cm
10 N
C
40 cm
10 cm
5N
D
40 cm
5 cm
?
Input force
Output force
Output distance
Fulcrum
1. According to this diagram and the table, which variable is being
changed?
A The fulcrum
C The output force
B The input distance
D The output distance
2. If the data in the table remains the same, what will be the input
force required to lift the object when the output distance is 5 cm?
F 2N
G 2.5 N
H 5N
J 10 N
Transparency Activities
Copyright © Glencoe/McGraw-Hill, a division of the McGraw-Hill Companies, Inc.
Input distance
3. Which hypothesis was probably tested by collecting these data?
A The input force decreases as the input distance decreases.
B The input force increases as the input distance decreases.
C The input force decreases as the output distance decreases.
D The input force increases as the output distance decreases.
Work and Machines
51