题目

John talked with me for about an houryesterday. Never before(I hear) him talk somuch. 答案：【1】had I heard下表是某同学为探索弹力和弹簧伸长的关系所测的几组数据： 弹力：F/N 0.5 1.0 1.5 2.0 2.5 弹簧的伸长x/cm 2.6 5.0 6.8 9.8 12.4（1）请你在图中的坐标线上坐出F-x图线（2）写出曲线所代表的函数式：______（x用cm作单位）（3）函数表达式中常数的物理意义：______．