一、假设物理量在解题过程中,常需要假设一些物理量的大小,而这些物理量并不需要求出其大小,假设只是为了便于列式进行计算.例1:(1998年丽水市自然科学中考试题).二个同种材料制成的实心圆柱体,高度相同.甲的质量是2千克,乙的质量是8千克,把它们竖直放在水平桌面上,则对桌面压强的大小 First, suppose the physical quantity in the process of solving the problem, often need to assume the size of some physical quantities, and these physical quantities do not need to find the size, the hypothesis is just to facilitate the column type to calculate. Example 1: (Lishui City, 1998 natural science middle school test questions ). Two solid cylinders made of the same kind of material, the same height. The mass of A is 2 kg, the mass of B is 8 kg. Place them vertically on a horizontal table, then the pressure on the desktop