“杆+导轨”模型是电磁感应问题的基本道具,也是电磁感应部分非常典型的题目类型.“杆+导轨”模型根据杆的数量分为“单杆”型和“双杆”型,根据导轨放置方式分为水平型、竖直型和倾斜型,外加磁场可恒定不变、均匀变化和非均匀变化,杆的运动状态可为匀速运动、匀变速运动、非匀变速运动等.由于“杆+导轨”模型组合形式多种,物理情景变化空间大,杆的运动情况复杂,涉及力学、电学多 “Rod + rail ” model is the basic props of electromagnetic induction problems, but also part of the electromagnetic induction is very typical topic type. “Rod + rail” model according to the number of rods is divided into Double rod “type, according to the rail is divided into horizontal type, vertical type and inclined type, the applied magnetic field can be constant, uniform and non-uniform changes in the movement of the rod can be uniform motion, uniform variable speed motion, non-uniform Uniform variable speed movement, etc .. Because of ”rod + rail " model combination of a variety of physical scene change space, the rod movement complex, involving mechanics, electricity and more