This is the gravitational potential energy. 这是重力势能(GPE)。
So you're using, then, the conversion of gravitational potential energy to kinetic energy. 所以你在利用,重力势能(GPE),转换成,动能。
Let me first give you the formal definition of gravitational potential energy. 我先给你一个对于,重力势能(GPE)的形式定义。
Notice that the gravitational potential energy increases. 注意,这里,重力势能(GPE)是增加的。
B1 which is closer to the Earth, notice that the gravitational potential energy decreases. 接近地球,,If,I,go,from,A,to,another,point,,B,prime,注意,重力势能(GPE),就会减小,我做负功。