单词：center of gravity path
单词：center of gravity path 相关文章
The events of September 11, 2001, in the United States are simply called 9/11. On that bright, clear morning 17 years ago, Al-Qaeda terrorists hijacked four large passenger airplanes to use as missiles of war. All four planes were flying across the c
2018年VOA慢速英语(九)月
Gravity 重力 What happens if you drop a book? 如果你丢一本书会发生什么？ Absolutely, it will fall down to the floor. This is called gravity. 很显然，书会掉到地上。这就叫做重力。 Gravity pulls from the center of the Ea
与美国小学生一起学英文第6册
Orbit 轨道 Do you know what an orbit is? 你知道什么是轨道吗？ An orbit is the path of a planet when it moves around the sun. 轨道是行星围绕太阳运动的轨迹。 It is similar to a cycling track. 它类似于自行车赛道。 As
与美国小学生一起学英文第12册
地球是太阳系从内到外的第三颗行星，也是太阳系中直径、质量和密度最大的类地行星。它也经常被称作世界。英语的地球Earth一词来自于古英语及日耳曼语。地球已有44～46亿岁，有一颗天然
英语听力文摘 English Digest
Did you ever dream of digging a hole so deep it came out the other side of the earth? Let's play that game again, using a little physics. First we have to imagine that our tunnel is lined with super-heat-resistant material so we can pass through laye
英语时差8，16
Last time we imagined a tunnel through the center of the earth. If such a thing existed, you could step into one end, fall all the way to the other side, and step out. Gravity would cause you to pick up almost exactly as much speed on the way down as
英语时差8，16