发布时间:2025-02-02 17:53:18
首先,mm2是指电缆截面即圆的面积(平方毫米),由面积公式:
S=π * r2=3.14*1/2R2=???mm2
比如:你说得如果不是四等芯的、不带钢带的即:由4.5CM=45mm便是3*150+1*70=520mm2的电缆。按照公式计算:r=√S/π=√520mm2/3.14==45mm==4.5CM
新搬的宿舍一摸墙壁掉粉有什么简单的方法处理一下床边的墙呢美不美观的无所谓别一觉醒来被子都是
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