斜轨法测量重力加速度影响因素的探讨

摘要

The inclined air track is usually used to measure the gravitational acceleration. However,the shape and the width of the barriers of the photogate and the inclined angle of the air track directly influence the measurement results. The influence of these factors on the measurement results is experimentally investigated and compared the results with the nominal value of the local gravitational acceleration (9.788 m/s2 in Guang-zhou).The results show that with a 2 cm high gaskets rail,the values obtained by a bar-type barriers are higher than the nominal value,whereas the value with a more than 13 cm width of the U-type barriers is higher than the nominal value.The other measurement values are lower than the nominal value.With the same inclined an-gle,the larger the distance between two barriers is,the higher the measured values are with U-type barriers.The larger the width of the barriers is,the lower the measured values are with bar-type barriers.%斜轨法是测量重力加速度的一种常用方法，但光电门挡光片的形状和宽度以及导轨的倾斜角度对测量结果有着直接的影响。本文从实验角度探讨上述几个因素对测量结果的影响并与当地重力加速度的标称值(广州9.788 m/s2)进行对比。测量结果表明：在导轨的垫片高度为2 cm时，使用条形挡光片的测量值均大于标称值；而U型挡光片宽度大于13 cm时测量值大于标称值，而小于13 cm时测量值则均小于标称值。在相同的导轨倾斜角下用U型挡光片时，两挡光片间距越大，测量值越大；而使用条形挡光片时，挡光片宽度越大，测量值就越小。