Centripetal Force Lab Report

In this experiment of centripetal force, a rubber bung attached to one end of a string which passes through a glass tube with smooth openings is whirled around in a horizontal circle (horizontal uniform circular motion). The glass tube has a number of screw nuts hanging at its other end.

After measuring the time taken t for the rubber bung to complete n revolutions, the angular velocity ω is obtained.
Then, we will attain the result : T = mω2 L where T and L are tension of the string and length of string respectively.


Compare the measured value of the tension T with the theoretical value mω2 L, we find there are discrepancies between them. This is because :
(i) there is friction acting at the opening where the string is in contact with the glass tube, causing T is not extactly equal to the weight of the screw nuts ;
(ii) the rubber bung is not whirled with constant speed ;
(iii) the string is not inextensible and
(iv) the rubber bung is not whirled in a horiztonal circle.

NB : The tension (measured value) can be found from the weight of the screw nuts, i.e. T = Mg where M is the mass of the screw nuts.

其實做TAS 係幾花時間
最好就有份可以參考下

我可以比一份centripetal force (circular motion) 比你, 其他就再傾傾啦

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