论文部分内容阅读
《物理教学》1992年第3期第34页载文——“一道力学习题解答”中给出的解答,列式完整,推理严谨。但笔者认为还存在一种更简捷有效的解法——系统分析法。解释如下:对轻弹簧,当我们用力 F 压它时,其压缩量 x 可由胡克定律 F=Kx 决定。当撤出外力 F 时,弹簧的伸长也是 x,就和我们用相同大小的力下拉它时能达到的伸长量一样,这一结论由系统能量守恒很容易证明。换句话说,当我们用力 F 压弹簧时,松手后弹簧伸长时,在效果上相当用同样大小的力下拉弹簧产生的
“Physics Education”, No. 3, 1992, No. 3, page 34, essay--“An Answer to a Problem in a Learning Question,” gives a complete, rigorous reasoning. However, I believe there is a more simple and effective solution - system analysis. The explanation is as follows: For a light spring, when we press it with force F, the amount of compression x can be determined by Hooke’s law F=Kx. When the external force F is withdrawn, the elongation of the spring is also x, which is the same as the amount of elongation that we can achieve when we pull it down with the same force. This conclusion is easily proved by the conservation of energy in the system. In other words, when we press the spring with force F, when the spring is released after loosening the hand, the same force will be used to pull down the spring.