Volcanoes and Plate Tectonics

PHYSICS: CHAPTER 4 VOCABULARY AND QUESTIONS Name______Chapter 4.1: Work and Machines 1. What is WORK?

2. In order for work to be done on an object, what must happen to the object?

3. In which of the following situations is work being done? a. Rolling a bowling ball b. Pushing on a tree for ten minutes c. Kicking a football

4. What is a JOULE?

5. How can you determine the amount of work done on an object?

6. Is more work done when a force of 2 N moves an object 3 m or when a force of 3 N moves an object 2 m? Explain

7. What is power?

8. How are power and work related?

9. Your laundry basket weighs 22 N and your room is 3 m above you on the second floor. It takes you 6 seconds to carry the laundry basket up. What is your power?

10. If you take only 4.4 seconds to carry the basket upstairs, what is your power?

11. A bulldozer does 72,000 J of work in 48 seconds. How much power does the bulldozer use?

12. The mythical god Atlas was believed to hold the weight of the sky on his shoulders. Was Atlas performing any work? Explain.

1 Chapter 4.2: How Machines Do Work Vocabulary: Define the following terms from Chapter 4.2.

1. Machine

2. Input force

3. Output force

4. Input work

5. Output work

6. Mechanical advantage

7. Efficiency

Assessment Questions

1. In what three ways can machines make work easier?

2. How does a screwdriver make work easier?

3. What is the mechanical advantage of a machine that changes only the direction of the applied force?

4. If a machine has an input force on 40N and an output force of 80N, what is its mechanical advantage?

5. What must you know in order to calculate a machine’s efficiency?

2 6. What is an ideal machine?

7. How is a real machine like an ideal machine, and how is it different?

8. The input work you do on a can opener is 12J. The output work the can opener does is 6J. What is the efficiency of the can opener?

9. Suppose the efficiency of a manual pencil sharpener is 58%. If the output work needed to sharpen a pencil is 4.8J, how much input work must you do to sharpen the pencil?

Chapter 4 Section 3 Questions (Use pages 124-135 in your textbook.) You MUST use complete sentences USE THE CHART FOR NUMBERS 1-3 1. Label the 6 simple machines in the chart. 2. For each of the 6 simple machines, give an example of something YOU use everyday that utilizes that machine. ex) wedge = knife Use examples not given in the text. 3. Explain how each of the 6 simple machines makes work easier. (use terms like force and distance…)

3 Name: Example of Use Name: Example of Use

How it makes work easier: How it makes work easier:

Name: Example of Use Name: Example of Use

4. How can you increase the mechanical advantage of a wedge?

5. What is the relationship between a screw and an inclined plane? Clue: try the Activity on pg. 127

6. Describe how the threads of a screw influence distance?

7. What is the lever? What is a fulcrum?

8. Diagram the use of a crowbar to lift an object. Label the effort force, resistance force, effort arm, resistance arm, and fulcrum.

9. What determines the class of a lever?

4 10. Diagram and label the 3 classes of levers. 1st Class Lever 2nd Class Lever 3rd Class Lever

11. What is a pulley? How can it make work easier?

12. What is a system of pulleys called? How does a system of pulleys increase mechanical advantage?

13. What is a wheel and axle? How do the sizes of the wheel and the axle relate?

14. Identify the following machines as 1st, 2nd, or 3rd class levers. see baseball fishing wheel door shovel crowbar tweezers hammer pliers saw bat pole barrow

15. Identify the following machines as Wheel and Axle, Pulley, Screw, or Wedge. knife, screwdriver, zipper, nut and bolt, gear, window shade, key, axe, boat sail, door knob, wind mill nut window boat door wind knife screwdriver zipper and gear key axe shade sail knob mill bolt