摘要:介绍一种测量重力加速度的新方法。在用三线摆测量转动惯量和验证平行轴定理的实验中都要用到重力加速度。因此，在已知转动惯量和平行轴定理的基础上，就可以推导出两种测量重力加速度的方法，一种是已知三线摆下圆盘的转动惯量，利用三线摆的转动周期公式变形，就可以得到三线摆测量重力加速度的实验公式；另一种是利用三线摆下圆盘上放两个质量相同的规则小圆柱体，但分布在不同位置，得到2个转动惯量，再通过平行轴定理的计算公式推导出测量重力加速度的实验公式。依据实验原理设计出实验方案，通过实验测量得到不同摆线长下所测量的重力加速度的结果。实验结果再以本地的重力加速度标准值作比较得出最佳的实验测量值，以此得到更加合理的三线摆测量重力加速度的最佳摆线长，为以后开展此实验提供一个简单、可行、准确度高的实验方法。

关键词：三线摆；重力加速度；转动惯量

Abstract:presents a new method of measuring acceleration of gravity. In the three-string- pendulum moment of inertia measurement and verification of parallel axis theorem experiment need to know basic physical constants. Therefore, the known moment of inertia and the parallel axis theorem based on the measurement can be derived are the acceleration of gravity method, a known three-string-pendulum moment of inertia under the disc, using the three formulas pendulum rotation cycle deformation can get three experimental pendulum gravity acceleration formula; Another is the use of three-disc release put both under the same rules as the quality of the small cylinder, but located in different locations, by two of inertia, parallel axis theorem then calculated by the formulas to the experimental measurement of acceleration of gravity formula. Experimental design based on principles of experimental program, measured by experiments under different cycloid length measured acceleration of gravity results. The results then the value of local acceleration of gravity compared to optimum standards of experimental measurements, thus get a more reasonable three-string-pendulum gravity acceleration best cycloid length to carry out this experiment for the future to provide simple, feasible, accurate experimental methods.

Keywords: Three-string- pendulum; Gravity acceleration; Rotational of inertia