书籍详情
格式
Kindle
页数
24
语言
英语
已发布
Jan 1, 2014
出版商
The Child's World
ISBN-10
1631431315
ISBN-13
9781631431319
描述
Readers learn how this simple machine makes it easier to lift and lower objects. They learn about fixed and movable pulleys and when it is best to use each. By the end of the book, readers know the difference between complex and simple machines and how pulleys are used in everyday life to make work easier.