题型:选择题 ____that Marie was able to set up new branches elsewhere.A.So successful her business wasB.So successful was her businessC.So her business was successfulD.So was her successful business 查看答案
题型:问答题 如图所示,用与水平成53°的力F将质量为m=6kg的静止物体从水平面上的A点拉到B点,AB=15m,物体与水平面间的动摩擦因数为μ=0.5.然后撤去水平力,物体冲上高为H=5m的光滑的斜面BC,水平面与斜面间有很小的光滑圆弧相接,物体冲到斜面顶时速度恰减小到零.求:(1)物体在B点的速度大小;(2)F的大小.(sin37°=0.6 cos37°=0.8) 查看答案