题目

题型：不详难度：来源：

（1）物体与接触面间的动摩擦因数μ＝?
（2）A、B之间的距离s_AB＝?

答案

（1）0.58（2）10 m

解析

(1) 物体在斜面上恰能匀速下滑，平行于斜面方向上的合力为零，则
mgsin30°=μmgcos30°                                                           ①
μ=="0.58··························································" ②
(2) 设物体从A→B的运动过程中加速度大小为a₁，B→C的运动过程中加速度大小为a₂，则
F－μmg＝ma₁··············································· ③
μmg＝ma₂··················································· ④
解得a₁＝ m / s²······································ ⑤
a₂＝10 m / s²⑥
根据题意有，····· ⑦
所以········································· ⑧
s_AB＝10 m···················································· ⑨
评分标准：本题共12分，其中①③④式各2分，②⑤⑥⑦⑧⑨式各1分。