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我们知道,对于放在水平面上的物体,压力是由于重力的作用产生的.并且压力的大小就等于重力的大小.假如物体的形状是正方体、长方体、圆柱体等,我们很容易由公式p=F/S推导出一个类似于液体内部压强的计算公式:p=F/S=G/S=pgV/S=pgh.由此可以看出:这一类压强也只跟组成固体的物质的密度和高度有关.下面通过具体的事例来分析、比较p=F/S和p=pgh的应用. 例1 三个高度和底面积都相同的铜、铁、铝圆柱体,竖直放在水平桌面上,对桌面的压强最大的是( ) (A)铜圆柱体(B)铁圆柱体
We know that for objects placed on a horizontal surface, the pressure is due to the action of gravity. And the size of the pressure is equal to the size of gravity. If the shape of the object is a cube, a cuboid, a cylinder, etc., we can easily use the formula p= F/S derives a formula that is analogous to the internal pressure of the liquid: p = F/S = G/S = pgV/S = pgh. From this it can be seen that this type of pressure also only follows the density of the solids that make up the solid. It is related to height. The following examples are used to analyze and compare the applications of p=F/S and p=pgh. Example 1 Three cylinders of copper, iron and aluminum with the same height and bottom area are placed vertically on a horizontal table. Above, the greatest pressure on the desktop is () (A) Copper cylinder (B) Iron cylinder