把一只羊用3米长的绳子系在一根木桩上,这只羊吃草的面积最多是多少平方米?
3.14×32,
=3.14×9,
=28.26(平方米);
答:这只羊吃草的面积最多是28.26平方米.
根据句意及首字母提示,补全单词。
1. I like English very much. I often go to the English c______.
2.—Where does the old man l______?
—He lives in Hainan.
3. I don't like the picture at a______. I like that one.
4. She seldom speaks Chinese, so her Chinese is p______.
5. Kangkang and Tongtong are in the same class. They are c______.
假设火星探测器距火星表面的高度为h,绕火星做匀速圆周运动的周期为T,火星的半径为R,引力常量为G,忽略其他天体对探测器的引力作用,试求:
(1)探测器线速度的大小;
(2)火星的平均密度;
(3)火星的第一宇宙速度.