Question

（1）物體與接觸面間的動(dòng)摩擦因數(shù)μ＝?
（2）A、B之間的距離s_AB＝?

Answer 1

（1）0.58（2）10 m

(1) 物體在斜面上恰能勻速下滑，平行于斜面方向上的合力為零，則
mgsin30°=μmgcos30°                                                           ①
μ=="0.58··························································" ②
(2) 設(shè)物體從A→B的運(yùn)動(dòng)過程中加速度大小為a₁，B→C的運(yùn)動(dòng)過程中加速度大小為a₂，則
F－μmg＝ma₁··············································· ③
μmg＝ma₂··················································· ④
解得a₁＝ m / s²······································ ⑤
a₂＝10 m / s²⑥
根據(jù)題意有，····· ⑦
所以········································· ⑧
s_AB＝10 m···················································· ⑨
評(píng)分標(biāo)準(zhǔn)：本題共12分，其中①③④式各2分，②⑤⑥⑦⑧⑨式各1分。