Physics Bifilar Pendulum - 11289 Words

Dimensional Analysis: Investigation on bifilar suspension Ho Yuk Him (Date of experimentation :20th and 29th October, 2010) This paper presents a study on the application of dimensional analysis on the formulation of an equation concerning the periodic time of a rod rotating at an angle about the vertical axis suspended by two strings at each end. We find that period is inversely related to distance between the strings parallel to each other and directly proportional to the both the square root of length of string and the length of suspension, (i.e. ï ½â€ž ). Although discrepancy is found when the equation proposed by eminent scholars is compared against with ours, our findings can hardly pale into insignificance as errors and the cause of†¦show more content†¦A synopsis is also given at this section. It is nearly impossible not to draw any reference during the compilation of this report and any papers referenced are given under the section, references. An appendices is attached at the end of this paper to outline the detailed derivation of formulas provided without proof in the section theory. II. Background A bifilar suspension is, literally, one in which two (bi) filaments (filar) support a rod. It is used in this study to show that the full relationship between the periodic time T, the length l of the vertical suspension threads and their distance d apart is: , (4) where M and l are the mass and the moment of inertia about the axis of oscillation respectively. The acceleration to gravity However, with limited resources and time, we manage just to establish the relationship among T, l , d and an additional unit f, length of suspension. Others are just ignored at the time being. Before going on discussing the hypothesis, it is worthwhile to get used to what equipments are used and how they are arranged. To make the experiment fair, extra apparatus are used. For the sake of convenience, all apparatuses employed with their respective quantities used are tabulated below: Apparatuses Ruler Specification 20 cm plastic 30 cm plastic 50 cm wood 100 cm wood Threads (Filaments) Stand and clamp Set square Spirit level Stop watch Wooden block Stickers / / / / Accurate to 0.01 seconds / / Quantities used 1 piece 1 piece