在力学、电学和热学的习题中,常可见着弹簧的“身影”,有弹簧的介入,使得这些习题的综合程度变强,在解答这些习题的过程中,可以形成若干解题技巧。下面,选析几例。请同学们在对这些问题的解答过程中,体会巧之所在。例1在光滑绝缘的水平面上,固定一个绝缘小球A,用轻质弹簧把A和另一绝缘小球B相连,设法使A、B带上等量同种电荷,平衡时,弹簧的伸长量为x1;现设法使A、B的带电量都减为原来的一半,平衡时,弹簧的伸长量为X2。则 In the exercises of mechanics, electricity, and thermals, the “shadows” of springs are often seen. With the intervention of springs, the comprehensive degree of these exercises becomes stronger. In solving these exercises, a number of problem-solving skills can be formed. Here are a few examples. Ask the students to understand where they are in the process of answering these questions. Example 1 In a smooth insulated horizontal surface, fix an insulated ball A, and connect it to another insulated ball B with a light spring. Try to make A and B carry the same kind of charge. When the balance is reached, the spring is stretched. The long amount is x1; now we try to reduce the amount of charge of A and B to half of the original, and the balance of the spring is X2. then