Get to know wheels and axles /

All people have jobs to do. Some jobs take a lot of energy. Simple machines help people get jobs done without working too hard. There are six kinds of simple machines: inclined planes, levers, pulleys, wedges, screws, and wheels and axles.

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Bibliographic Details
Online Access:Electronic book from EBSCO
Main Author: Challen, Paul C. 1967-
Format: eBook
Published:New York, NY : Crabtree Pub. Company, 2009.
Series:Get to know simple machines.