v = 108*1000/3600 = 30m/sL = 50m(1)求过程中加速度大小a = v^2/(2L) = 30^2/(2*50) = 9m/s^2(2)若改变测评路面,初速度乃为108km/h,制动加速度变为6m/s制动时间t' = v/a = 30/6 = 5s制动后6秒内位移 = 制动距离 = v...