例1 如图1,用弹簧测力计在空气中称得某合金块所受重力为2牛.把合金块浸没在水中,弹簧测力计的示数为1牛.由此,该弹簧测力计连同合金块,就成为一个“液体密度秤”.用它能够测量某些未知液体的密度.使用时只要将合金块浸没在待测液体中,就可以从弹簧测力计指针指示的位置读出液体的密度.现请你在弹簧测力计刻度板右侧标出该“密度秤”的“0”刻度和能够测量的最大值刻度. Example 1 As shown in Fig.1, the gravity of a certain alloy block is measured as 2 lbs in air by a spring dynamometer. The alloy block is immersed in water and the spring dynamometer is shown as 1 quart. Thus, the spring test The force meter, together with the alloy block, becomes a “liquid density scale.” It can measure the density of some unknown liquid. When used, the alloy block can be immersed in the liquid to be measured, and the position indicated by the spring dynamometer pointer can be used. Read the density of the liquid. Now mark the “0” scale of the “density scale” and the maximum scale that can be measured on the right side of the spring dynamometer scale plate.