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有些常见题,不但学生经常做错,甚至教师有时也容易讲错.本人觉得有必要详细分析一下,以免再错. 例1.如图1所示,竖立在水平地面上的轻弹簧,下端与地面固定,将一金属球放置在弹簧顶端(球与弹簧不粘连),并用力向下压球,使弹簧作弹性压缩,稳定后用细线把弹簧拴牢,如图1所示.烧断细线,球将被弹起,脱离弹簧
Some common questions, not only students often make mistakes, and even teachers are sometimes easy to make mistakes. I think it is necessary to analyze in detail, so as not to mistake. Example 1. As shown in Figure 1, light spring erected on the level of the ground, the bottom with Fix the ground, place a metal ball on the top of the spring (the ball does not stick to the spring), and press the ball down firmly to make the spring elastically compressible. After stabilizing, use a thin wire to fasten the spring, as shown in Figure 1. Thin line, the ball will be bounced off the spring