(9分)某实验小组探究弹簧的劲度系数k与其长度(圈数)的关系；实验装置如图(A)所示：一均匀长弹簧竖直悬挂，7个指针p₀、p₁、p₂、p₃、p₄、p₅、p₆分别固定在弹簧上距悬点0、10、20、30、40、50、60圈处；通过旁边竖直放置的刻度尺，可以读出指针的位置，p₀指向0刻度；设弹簧下端未挂重物时，各指针的位置记为x₀；挂有质量为0.100kg砝码时，各指针的位置记为x；测量结果及部分计算结果如下表所示(n为弹簧的圈数，取重力加速度为9.80m/s²).已知实验所用弹簧的总圈数为60，整个弹簧的自由长度为11.88Cm.&nBsp&nBsp&nBsp&nBsp&nBsp&nBsp&nBsp&nBsp&nBsp&nBsp&nBsp&nBsp&nBsp&nBsp&nBsp&nBsp&nBsp&nBsp&nBsp&nBsp&nBsp&nBsp&nBsp&nBsp&nBsp&nBsp&nBsp&nBsp&nBsp&nBsp&nBsp&nBsp&nBsp&nBsp&nBsp&nBsp&nBsp&nBsp&nBsp&nBsp&nBsp&nBsp&nBsp&nBsp&nBsp&nBsp&nBsp&nBsp&nBsp&nBsp&nBsp&nBsp&nBsp&nBsp&nBsp&nBsp&nBsp&nBsp&nBsp&nBsp&nBsp&nBsp&nBsp&nBsp&nBsp&nBsp&nBsp&nBsp&nBsp&nBsp&nBsp&nBsp&nBsp&nBsp&nBsp&nBsp&nBsp&nBsp&nBsp&nBsp&nBsp&nBsp&nBsp&nBsp&nBsp&nBsp&nBsp&nBsp&nBsp&nBsp&nBsp&nBsp&nBsp&nBsp
图(B)中画出的直线可以近似认为通过原点；若从实验中所用的弹簧截取圈数为n的一段弹簧，该弹簧的劲度系数k与其圈数n的关系的表达式为k={{u}} ③ {{/u}}n/m；该弹簧的劲度系数k与其自由长度l0(单位为m)的表达式为k={{u}} ④ {{/u}}n/m.