Eleven point two kilometers per second, at which satellites can be freed from the gravitation of the earth, is called "escape speed".
卫星以11.2千米每秒的速度前进可以脱离地球引力,这被称为“逃逸速度”。
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One of them is the force of gravitation (地心引力), which tries to pull the satellite towards the earth and is like a rope which keeps the satellite from flying away.