论直线运动中拉力F的极值

Extremun of Pull(F)in Rectilinear Motion

在直线运动中拉力F的极值随摩擦系数 μ的变化而变化 ,当θ=α=arctgμ( μ为摩擦系数 ,θ角为拉力F和运动方向的夹角 )时 。

In rectilinear motion,the extremum of pull(F)varies with the factor;angleθ=α=arctgμ(μ:friction factor;angleθ:the angle between the direction of pull and the motion direction).pull(F)has its minimum.