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《物理通报》(1996.1)发表王晓秋老师的文章,认为:不宜依密度的关系判断物体的浮沉。笔者认为:有必要将物体浮沉的条件和判断物体浮沉的判据区别开来。物体的浮沉条件即物体的上浮和下沉应具备的条件,具体地讲,就是:如果物体所受各力的合力,方向是向上的,物体就上浮;方向是向下的,物体就下沉;合力为零,物体就是静态的。对于物体只受重力和浮力作用的简单情况,就是浮力和重力的大小关系。为此,现行教材中已给出明确的表述:浸没在液体里的物体,如果所受的浮力大于重力,物体就上浮;如果浮力小于重力,物体就下
“Physics Bulletin” (1996.1) published Wang Xiaoqiu’s article, saying: It is not appropriate to judge the floating of objects according to the relationship of density. The author believes that it is necessary to distinguish the conditions of floating objects from the criteria for judging the floating of objects. The floating condition of an object is the condition that the object should float and sink. Specifically, if the object is subjected to the force of each force and the direction is upward, the object floats; when the direction is downward, the object sinks. The resultant force is zero and the object is static. The simple case where the object is only affected by gravity and buoyancy is the relationship between the buoyancy and gravity. To this end, the current teaching material has given a clear statement: objects immersed in liquid, if the buoyancy is greater than gravity, the object will float; if the buoyancy is less than gravity, the object will be