今年我市举行初二物理竞赛有这样一道题:质量M=50千克的钢质机器,为了使它减轻100牛顿,现将机器的部分钢件改为铝质件,问至少需要多少千克铝件来代替钢件才符合要求?(p_钢=7.8×10~3千克/米~3,P_铝=2.7×10~3千克/米~3,g取10牛/千克) 分析学生解题情况。主要错误有两种: 错解1:因为换下钢件的体积V=m/p_钢 This year the city held the second year physics competition with this question: Quality M = 50 kg of steel machinery, in order to reduce it 100 Newtons, now part of the machine’s steel to aluminum, asked at least how many kilograms of aluminum Replace the steel to meet the requirements (p_steel=7.8×10~3kg/m~3, P_aluminum=2.7×10~3kg/m~3, g takes 10 N/kg) Analyze students’ problems Happening. There are two major errors: Mistake 1: Because the volume of steel replaced V = m/p_ steel