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在浮力的习题教学中,有这样一个常见的习题: 在木棒的下端绕上适量的铁丝,便能使它竖直漂浮在水面上.如果将它露出水面的部分全部截去,余下部分将:(A)上浮一些.(B)下沉一些.(C)既不上浮,也不下沉.(D)无法判断. 答案大家都知道是(A)上浮一些,如果我们再将露出水面部分切去,它仍会上升.将露出水面部分不断切去,整体就不断会上升,最终会怎样?有没有可能突然沉下去呢?(它下面可是铁丝)下面让我们共同推证一
In buoyancy exercises, there is a common problem: When the appropriate amount of wire is wrapped around the bottom end of the stick, it can float vertically on the water. If the part that exposes it to the water is completely cut off, the rest will be :(A) floats upwards. (B) sinks some. (C) neither floats nor sinks. (D) can’t judge. The answer everyone knows is (A) goes up a bit if we are going to expose the water partially When it goes, it will still rise. The part of the water surface will continue to be cut off. The whole will continue to rise. What will happen eventually? Is it possible to sink suddenly? (It is a wire underneath it.) Let us jointly deduce one.