Method for measuring gravitational acceleration by utilizing increase of radius of pendulum bob

Abstract

The invention provides a method for measuring the gravitational acceleration by utilizing increase of the radius of a pendulum bob. According to the method, a calculation formula of the gravitational acceleration g is obtained by analyzing the swinging period of a compound pendulum system consisting of a swinging rod and cylindrical weights, researching the change of the swinging period of the compound pendulum system when the radiuses of the cylindrical weights with the radiuses of r2 and r1 are gradually increased by step lengths of r2 and r1 and comparing the influences on the swinging period caused by different step lengths. Compared with the current experimental methods widely adopted, the method provided by the invention has the advantages that from the experimental principle, the equivalent pendulum length can be obtained without depending on changing the position of the compound pendulum system from a mass center to a suspension point, and the value of the gravitational acceleration obtained by the slope of a fitting line is realized by analyzing the influence of the step lengths in radius change of the pendulum bob on the swinging period, so that the complex and tedious data processing work is reduced, the data processing speed is increased, the data processing error is reduced; and the method adopts a simple and definite principle and is convenient to understand and is suitable for being operated by students.

Description

technical field [0001] The invention relates to an experimental device, in particular to a method for measuring the acceleration of gravity by increasing the radius of a pendulum. Background technique [0002] In the experiment of measuring the acceleration of gravity with the compound pendulum in the university physics experiment, a slender pendulum rod with equidistant round holes is generally used. The surface of the pendulum rod is marked with vertical scales. In the experiment, one of the round holes of the pendulum rod is hung on the bracket Swing, record the distance from the circular hole to the center of the swing rod and the swing cycle when the circular hole is suspended, then draw a graph on the coordinate paper, use the graphic method to process data and calculate the acceleration of gravity. The principle is to change the position of the suspension point to obtain the swing period of the pendulum at different distances from the suspension point to the center of...

AI Technical Summary

Problems solved by technology

[0004] In the actual operation process, the above-mentioned widely used compound pendulum measurement gravitational acceleration experiment has the following difficulties. The first is that the periodic curve is a traced curve. Unlike the fitted straight line, it is very difficult for beginners to describe an accurate curve; There is a deviation between the traced periodic curve and the real curve, so the coordinate values ​​of the four points where the straight line parallel to the abscissa axis intersects the periodic curve must also have deviations; third, because the measurement points are discrete data, the abscissa interval is generally 2cm , such an interval is difficult to find exactly the same measurement points for four periods in reality

In summary, there are large deviations in the existing measurement acceleration experiments, and the data measurement and processing process is also relatively cumbersome and time-consuming

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