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 Glencoe Science Photo Credits Section Focus Transparency 1: R. Rowan/Photo Researchers; Section Focus Transparency 2: Michael Javorka/Stone; Section Focus Transparency 3: Jeff Greenberg/Visuals Unlimited; Teaching Transparency: (t) Amanita Pictures, (b) Glencoe file photo Copyright © by The McGraw-Hill Companies, Inc. All rights reserved. Permission is granted to reproduce the material contained herein on the condition that such material be reproduced only for classroom use; be provided to students, teachers, and families without charge; and be used solely in conjunction with the Work and Machines program. Any other reproduction, for use or sale, is prohibited without prior written permission of the publisher. Send all inquiries to: Glencoe/McGraw-Hill 8787 Orion Place Columbus, OH 43240-4027 ISBN 0-07-866060-2 Printed in the United States of America. 1 2 3 4 5 6 7 8 9 10 067 08 07 06 05 04 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
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