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1.用公式和例1 如图1所示,边长为10cm的正方形木块,已知木块的密度是0.8·103kg/m3,用细线悬挂并放于一底面积为400cm2的盛水的圆柱形容器中.此时,细线对木块的拉力为2N,若细线能承受的最大拉力为5N,打开容器底部阀门K放水,求放出多少kg水细线刚好被拉断?(g取10N/kg) 解析如图2所示,当细线
1. Formula and Example 1 As shown in Fig. 1, a square wooden block with a side length of 10cm is known to have a density of 0.8103kg/m3, suspended with a fine wire and placed in a water with a bottom area of 400cm2. In the cylindrical container, the pulling force of the thin wire on the wooden block is 2N. If the thin wire can withstand the maximum pulling force of 5N, open the valve K at the bottom of the container and release the water. How many kg of the water thin wire should be released just to be broken? g takes 10N/kg) Analysis as shown in Figure 2, when the thin line