如图所示的电路中，电阻R₁的阻值为10Ω。闭合开关S，电流表A₁的示数为0.6A，电流表A₂的示数为0.4A，则电阻R₂的阻值为____ Ω。若电流表A₁发生短路，则电流表A₂的示数将____ 。（填“不变”、“变大”或“变小”）

    Mr. White lives in the countryside with his wife, Mrs. White. From Monday to Friday he works in a small office near his house. He is free on Saturdays and Sundays. He has a nice garden near his house. He likes growing flowers and he usually works in the garden on Saturdays and Sundays. The flowers are colourful and beautiful. Mrs. White likes them very much. She often helps Mr. White. They live happily together.

患肾炎的张大爷经过治疗已恢复健康，他的尿液中不再含有大分子蛋白质和葡萄糖．这分别是（   ）

（1）下面图A、B、C可以说明力改变了 ____．

A、图中守门员按住球，求由运动变为静止；

B、图中足球运动员踢球，球由静止变为运动；

C、普通足球运动员用头顶球，球的方向改变了．

（2）下面图D、E说明了力可以 ____．

D、图中小明用力拉弹簧，弹簧伸长了；

E、图中小明用力弯锯条，锯条变弯了．