A:失去雏鸡的母鸡抚爱小猫
B:蚯蚓走“T”形迷宫
C:小黑猩猩模仿取食白蚁
D:猴子表演骑车
—What's your idea about family education?
— kids learn to be independent, it is for their future.
如图所示,用“碰撞实验器”可以验证动量守恒定律,即研究两个小球在轨道水平部分碰撞前后的动量关系.