题目

如图所示，窗子上、下沿间的高度H=1.6m，墙的厚度d=0.4m，某人在离墙壁距离L=1.4m、距窗子上沿h=0.2m处的P点，将可视为质点的小物件以v的速度水平抛出，小物件直接穿过窗口并落在水平地面上，取g=10m/s2。则v的取值范围是（ ）A.v>7m/s B.v<2.3m/sC.3m/s<v<7m/s D.2.3m/s<v<3m/s 答案：【答案】C【解析】小物体做平抛运动，恰好擦着窗子上沿右侧穿过时v最大。此时有，代入数据解得vmax=7m/s恰好擦着窗口下沿左侧时速度v最小，则有，代入数据解得vmin=3m/s故v的取值范围是3m/s＜v＜7m/s故C正确ABD错误。故选C。Richard Gere ________ a super model called Cindy Crawford in 1991, but they ended their marriage in 1995. Actually, they _________ only for four years since they fell in love with each other.A. was married to; got married B. got married to; have marriedC. married; have been married D. got married with; are married