The force may taper off, the force may not be given by a straight line, but for modest deformations, every spring will have a linear regime in which the force is linearly proportional to the stretching.

它产生的力可能会渐渐消失,力的曲线可能不是一条直线,而有轻微的弯曲,每个弹簧都有一个线性区间,在这一区间内,力和伸长量是线性关系

耶鲁公开课 - 基础物理课程节选

First, we got to make sure the spring exerts a fixed force every time.

首先,要保证,弹簧每次产生的力是恒定的

耶鲁公开课 - 基础物理课程节选

If every time I get the same acceleration, I'm convinced this is a reliable spring that is somehow producing the same force under the same condition.

如果每次都能得到相同的加速度,这个弹簧的可靠性就能令人信服,即它在相同的条件下能够产生相等的力

耶鲁公开课 - 基础物理课程节选