Name _______________________________________________ Date ________________ Class______________ CHAPTER 5 DIRECTED READING WORKSHEET Work and Machines As you read Chapter 5, which begins on page 110 of your textbook, answer the following questions. “One, Two . . . Stroke!” (p. 110) 1. What makes the Dragon boats move? Pre-Reading Questions (p. 110) Answer these questions in your ScienceLog now. Then later, you’ll have a chance to revise your answers based on what you’ve learned. Start-Up Activity (p. 111) CHAPTER 5 3. What is the purpose of this activity? Section 1: Work and Power (p. 112) ▼ ▼ ▼ Copyright © by Holt, Rinehart and Winston. All rights reserved. 2. What is this team doing as they compete in Hong Kong’s Dragon Boat Races? 4. In the scientific sense, you are doing work on this page by reading this question. True or False? (Circle one.) TEXAS EDITION, GRADE 7, UNIT 2 RESOURCES 15 Name _______________________________________________ Date ________________ Class______________ Chapter 5 Directed Reading, continued The Scientific Meaning of Work (p. 112) 5. When you bowl, you are applying a to the bowling ball that makes it move a certain distance. 6. When you are carrying a heavy suitcase at a constant speed, you are not doing work. Why not? 7. Look at Figure 3. Which of the following is having work done on it? (Circle all that apply.) a. b. c. d. a a a a carton as you push it at a constant speed backpack as you walk at a constant speed grocery bag as you pick it up grocery bag as you carry it at a constant speed applied to the object and d is the through which the force is applied. 9. Suppose you want to calculate how much work it takes to lift a 160 N barbell. Besides the weight of the barbell, what other information do you need to know? a. b. c. d. the shape of the weights how high the barbell is being lifted the strength of the person doing the lifting none of the above Power—How Fast Work Is Done 10. The power. (p. 115) is the unit used to express 11. If you increase power, you are increasing the amount of work done in a given amount of time. True or False? (Circle one.) Section Review (p. 115) Now that you’ve finished Section 1, review what you learned by answering the Section Review questions in your ScienceLog. 16 HOLT SCIENCE AND TECHNOLOGY Copyright © by Holt, Rinehart and Winston. All rights reserved. Calculating Work (p. 114) 8. In the equation for work, F is the