Water injection to extend compound pendulum pendulum length to measure gravitational acceleration

Abstract

A method for measuring gravitational acceleration by increasing the pendulum length of a compound pendulum through water injection relates to the field of physical test instruments and test methods. The method is designed for overcoming the shortcomings that the data measurement process and the data processing process are cumbersome and time-consuming and reducing deviation caused by calculation. According to the technical scheme, a pendulum rod is composed of the pendulum rod lower portion, a cup cover and a forming cap, the distance from the mass center to the central axis of a hanging rod is 0.30-0.32 times of the overall length of the pendulum rod, the pendulum lower portion is in a hollow cylindrical shape, the bottom is sealed, the upper end is open, the opening is called a cup rim, the cup rim is provided with the cup cover, the cup cover is in threaded connected with the cup rim, and a seal gasket is arranged on a platform at the lower end of the cup rim and between the cup cover and the cup rim. The outer side of a rubber bag is covered with the forming cap, a locating rod fixed to the outer side face of the forming cap penetrates through two rows of locating rings, the locating cap is a hollow cylinder, the material, the inner diameter and the outer diameter of the forming cap are the same as the pendulum lower portion, a water injection pipe is arranged at the lower portion of the pendulum rod and at the position of the hanging rod, and a check valve is arranged in the water injection pipe. The method for measuring gravitational acceleration by increasing the pendulum length of the compound pendulum through water injection has the advantages that a measurement device and the measurement process are simple and clear, and data processing is simple and fast.

Description

technical field [0001] The invention relates to the field of experimental equipment and experimental methods, in particular to the experiment of measuring the acceleration of gravity with a compound pendulum in a physical experiment. Background technique [0002] In the experiment of measuring the acceleration of gravity with the compound pendulum in the university physics experiment, a long pendulum rod with equidistant circular holes is generally used. There are scales on the surface of the pendulum rod. The hole is hung on the hanging rod (the hanging rod is fixed on the bracket) to swing, measure the swing cycle, record the position coordinates of each hole when hanging (the distance from the round hole to the center of the swing rod, or the origin of other coordinates) and the The swing period when the circular hole is suspended, and then draw a graph on the coordinate paper, and use the graphical method to calculate the acceleration of gravity. [0003] "University Ph...

AI Technical Summary

Problems solved by technology

[0005] Since the measurement points are discrete data, the abscissa interval of the discrete data is generally 2cm, and the interval is relatively long. Generally, it is impossible to find that the cycle of the four measurement points is exactly the same. The cycle curve is a traced curve, which deviates from the real curve, so make a The four points where the horizontal line intersects the deviated h-T curve, the coordinate values ​​of the abscissa read from the four points also have deviations, so in addition to the error of the experiment itself, the graphical calculation method also brings a large deviation, Moreover, the data measurement process and processing process are cumbersome and time-consuming

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