题干
从右栏中找出左栏各句的应答语。
①What does he look like?____ A. It's yellow.
②Is his bike new?____ B. Yes, they are.
③Whose book is this?____ C. He has gray hair.
④Are these your apples?____ D. Sorry, I don't know.
⑤What color is your coat?____ E. It's mine.
答案(点此获取答案解析）
C,D,E,B,A
的轻杆下端固定一个质量为
的小球，上端连在光滑水平轴上，轻杆可绕水平轴在竖直平面内运动（不计空气阻力）．当小球在最低点时给它一个水平初速度
，小球刚好能做完整的圆周运动．若小球在最低点的初速度从