不同摆角对三线摆测量转动惯量的影响

The Effect of Different Pendulum Angle on Measurement of the Rotational Inertia Using Three-wire Pendulum

采用三线摆法测量物体的转动惯量，讨论在大摆角（大于5°）下悬盘、圆环和圆盘的转动惯量与理论值的差距，发现当摆角在5°～15°时三种待测物的测量结果误差均在5％以内，而当摆角取2°～3°时，周期测量值的起伏反而较大，导致转动惯量的测量值误差较大。所以笔者认为在实验中对摆角的要求不需严格规定在小于5°的范围内，只要不超过15°即可。

In this paper ,the method of three-wire pendulum is adopted to measure the Rotational Inertia of the wheel,the circle,as well as the disk in order to find the deviation between the experiment results and the theoretical results when the pendulous angle is over 5 degrees.Through the experiment , it is found that the percentage error of the experiment results is less than 5 percents when the pendulous angle is between 5 and 15 degrees.But when pendulous angle is between 2 degrees and 3 degrees, the ups and downs of the cycle measured values become bigger , and this results in bigger error .Thus, when doing the experiment, it is not necessary to limit the pendulous angle less than 5 degrees, and it is rational as long as the angle is no more than 15 degrees.