1·Now I'm really fantastic at drawing this mechanical device, but you can imagine that dropping weight can cause a paddlewheel to turn.
现在我真的很沉迷机械装置，但是你可以想象重物掉落的时候会带动桨轮旋转。
2·It's a trivial matter, by looking at what is the weight and how far does it drop, to say OK, how much work is done by the paddlewheel.
这是一个很简单的问题，通过观察重量是多少以及它下降了多远，来确定桨轮做了多少功。