http://www.ck12.org Chapter 8. Work, Power, and Simple Machines
CHAPTER
8 Work, Power, and Simple Machines
Chapter Outline
8.1 Work
8.2 POWER
8.3 SIMPLEMACHINES
8.4 REFERENCES
If you push against a wall with all your strength for a full minute, how much work have you done? You might think
you’ve worked very hard, but you actually haven’t completed any work, as defined by physics. Completing work
from a physics standpoint requires not only force but also movement of an object.
Imagine trying to lift a 400-pound object, such as the orange box shown above. Could you do that by yourself? If
you simply leaned over and tried to pick it up, you’d never be able to. However, a series of pulleys such as the system
shown above would allow a single person to lift a 400-pound object without any other assistance.
This chapter examines physics’ definition of work, the relationship between work, force, and power, and the
mechanical assistance provided by simple machines.