描述
Pulleys are simple machines used to lift and move loads. Builders use pulley systems to lift tools or materials up high and elevators go up and down with the help of pulleys. Kids will learn how pulleys make work easier and how they are often part of complex machines.
書籍詳情
格式
電子書
頁數
25 頁
語言
英語
已出版
Aug 1, 2009
出版商
Bellwether Media
版本
2 個版本
ISBN-10
1612115047
ISBN-13
9781612115047