杆秤一端粗，一端细，但刻度却均匀．为什么？如图1，设秤杆和秤钩的质量为m，重心在B点．把质量为m0的秤驻挂在O点（杆秤的零刻度起点），杆秤处于空载平衡状态．由杠杆的平衡条件得如图2，在秤钩上挂一质量为M的物体把秤砧移至D点，杆秤再度处于平衡状态．则有对已制成的杆秤 One end of the scale is thick and one end is fine, but the scale is uniform. why? As shown in Figure 1, set the weight of the balance bar and the scale hook to m, and the center of gravity at point B. Weigh the scale with mass m0 at point O (zero scale starting point of the steelyard), and the scale is in no-load equilibrium. The balance condition of the lever is shown in Fig. 2. Hang an object with mass M on the hook of the scale and move the scale anvil to point D. The balance is again in balance. There is a steelyard scale