Physical Science
Work and Simple Machines
Chapter 8 Study Guide
1. What is the scientific meaning of the word “work”?
2. If you throw a ball, are you doing work? Explain your answer. Be sure to include
information about when throwing a ball is work and when it is not.
3. If you are pushing against a wall, are you doing work? Explain your answer.
4. Refer to the chart on page 189 (or on your notes from class): If you are carrying a
suitcase, are you doing work on the suitcase? Why or why not?
5. Complete your own version of the chart.
Example
Direction of force
Direction of motion
6. What two things do we need to know to calculate work?
Doing work?
7. What is the formula for calculating work? (Be sure to review your homework so
that you can use the formula.)
8. What is “power”, scientifically speaking?
9. What is the formula for calculating power? (Review your homework to make sure
you can use the formula.)
10.What is a machine?
11.Draw an example of a machine that you use in your day-to-day life, and explain it.
12.What is a lever? Draw an example of a lever and explain how it works. List two
other examples of a lever.
13.What is the fulcrum of a lever?
14. What is an inclined plane?
15. Draw an example of an incline plane and describe how it works.
16. What is a wedge?
17. Draw a picture of a wedge and describe how it works. Name at least two other
wedges.
18. What is a screw?
19. Draw an example of a screw and explain how it works. Name two other types of
screws.
20. What is a wheel and axle?
21. Draw an example of a wheel and axle and describe how it works. Name two other
wheels and axles.
22. What is a pulley?
23. What are compound machines? Draw and describe an example. Name two other
compound machines.
24. Does a machine reduce the amount of work that is being done? Explain your
answer.
25. If machines do not reduce the amount of work being done, how do they help us?
26.What is a machine’s mechanical advantage? If I say a machine has a mechanical
advantage of 20, what does that mean?
27.What is mechanical efficiency?
Students in honors classes need to know the formulas for work and
power. Students in academic classes will be given these formulas. All
students need to be able to use the formulas.