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改变物体内能的方法有两种:热传递和做功.而且,做功和热传递对改变内能的效果完全是等效的.所以,摩擦很容易使物体温度升高.这样看来,利用摩擦的方法取火似乎是一件很容易的事情.可是实际做起来却不这样简单.很多著作中都曾讲述过摩擦取火的故事,著名作家马克·土温就曾经讲过一个故事,说他自己想实现摩擦取火的经过,他说:“我们每个人各取了两条棒,开始相互摩擦.两个小时以后,我们人都冻僵了,木棒也一样冻得冷冰冰的.”(事情发生在冬天)可以说上述这两个小时的摩擦,假如他们所付出的能量
There are two ways to change the internal energy of an object: heat transfer and work. Moreover, work and heat transfer are completely equivalent to changing internal energy. Therefore, friction can easily increase the temperature of an object. In this sense, friction is used. The method of taking fire seems to be an easy task. However, actually it is not so simple. Many books have told the story of friction and fire. The famous writer Mark Towin once told a story about him. He wanted to realize the process of friction and fire, and he said: “We each took two sticks and started to rub against each other. Two hours later, we were all frozen and the sticks were just as cold.” "(what happened in the winter) can be said that these two hours of friction, if they pay the energy