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浮力的计算是初中物理力学中的难点和重点,也是全国各地的中考物理命题压轴题的重点和热点,主要命题型式:一是直接运用浮力的几种求法直接求物体在液体中受到的浮力、液体的密度;二是通过与密度联系,求物体的密度、体积、质量、重力及物体受到的浮力;三是与压强结合命题,如改变物体所受浮力的大小,计算液体产生压强的变化．所以浮力的计算学习对初中物理来说非常关键．笔者多年对全国各地试题的研究,总结归类得出作为中考压轴题的浮力计算大体分为二大类．浮力的四种求解法 1．阿基米德原理法公式:F浮=G排=m排g =ρ液gV排① 2．弹簧测力计法公式:F浮=G物-F拉(拉
The calculation of buoyancy is a difficult and important point in the physics and mechanics of junior middle school. It is also a focal point and hotspot of the physics proposition title problem in the national examinations. The main proposition type is as follows: First, several kinds of direct buoyancy methods are used to directly determine the buoyancy of objects in liquids. The density of the liquid; Second, through the contact with the density, find the density, volume, mass, gravity and buoyancy of the object; the third is combined with the pressure proposition, such as changing the size of the buoyancy of the object, calculate the liquid pressure changes. Therefore, the buoyancy calculation learning is very important for junior high school physics. For many years, the author’s research on the examination questions in various parts of the country has been summarized and classified as two major categories of buoyancy calculations. Four methods of buoyancy Archimedes principle method formula: F floating = G row = m row g = ρ liquid gV row 1 2. Spring dynamometer formula: F float = G object - F pull (pull