查人人中国名人网北京故宫路线图:请教一道高一物理题目~！
来源：百度文库 编辑：查人人中国名人网 时间：2024/05/02 18:35:50
某物从倾角37度的斜面底端A沿斜面上滑,物与斜面摩擦系数为0.5,当到B时动能为E,到最高点C又滑到AB的中点D时动能也是E,已知向量AB=10m,求BC长
````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````C／
````````B／
````````／
````D／
````／
A∠___________
````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````C／
````````B／
````````／
````D／
````／
A∠___________
BC=1.25m.
从B点到D点的过程中应用动能定理:重力所做的正功和摩擦力所做的负功相等,总功为零,所以有:mgBDsin37°=μmg(2BC+BD)cos37°,所以BC =1.25m.