Laboratory work 8 Simple, Physical and Torsional Pendulum

This paper looks at the physics behind oscillatory motion and how this can be applied to many different scenarios including using different types of pendulums to explain the phenomena of SHM and DHM (simple and damped harmonic motion respectively). Written as part of my A-Level Physics course (OCR B Advancing Physics) in Autumn 2014 (Nov 2014-Jan 2015)

Lat. Am. J. Phys. Educ. Vol. 3, No. 2, May 2009

We propose a new tool for laboratory curricula based on computer-aided data acquisition and analysis. A pendulum coupled to a low-friction rotary sensor offers variable length, variable mass, variable oscillation plane (to change the effective gravitational restoring torque) and two different kind of damping torque: “dynamic friction” (almost constant) and “viscous” proportional to the angular velocity. Simple models implemented in common spreadsheets allow to compare the experimental results with the theoretical predictions

• General Background: A mass m hanging from a string whose length is L and a pivot point on which this mass is fixed are what a simple pendulum (which was discovered during the 10 th century by Ibn Yusuf) consists of. During the 17 th century, it is developed by some physicist, especially by Galileo. When the mass hanging from the string is released with an initial angle, it starts to move with a periodic motion. The motion can be approximated as a simple harmonic motion if the pendulum swings through a small angle (so sin (ө) can be approximated as ө). The frequency and period for the simple pendulum are the independent of the initial angle of the movement (initial position of the mass to the vertical reference line). In addition to the initial angle of the mass, the period doesn't depend on the mass of the object. However, it is affected by the length of the string which the mass is hanged on and the acceleration of gravity. The most widespread applications of the simple pendulum are for timekeeping, gravimetry (the existence of the variable g in the period equation of simple pendulum-• means that the pendulum frequency is different at different places on Earth), seismology, scholar tuning, and coupled pendula. It is also used for entertainment and religious practice. • Aim: To determine the effects or contribution of the length of the string on the period for the simple pendulum and find out a mathematical relationship between the length and the period. • Hypothesis: Since the length of the string which the mass is hanged on is shortened, the magnitude of the period for the simple pendulum gets increased. Different masses of the object hanging from the string have no effect on the period.

European Journal of Physics, 2005

We describe a 8085 microprocessor interface developed to make reliable time period measurements. The time period of each oscillation of a simple pendulum was measured using this interface. The variation of the time period with increasing oscillation was studied for the simple harmonic motion (SHM) and for large angle initial displacements (non-SHM). The results underlines the importance of the precautions which the students are asked to take while performing the pendulum experiment.

Journal of Natural Sciences and Mathematics Research

Every object has a tendency to maintain its state of motion. The concept also applies to rotating objects called moments of inertia. This experiment aims to explain the working principle and determine the magnitude of the moment of inertia of objects using a bifilar pendulum teaching aid based on the ATMEGA-16 microcontroller. The implementation method used is the experimental method. The working principle of the ATMEGA-16 bifilar pendulum microcontroller-based teaching aids uses the bifilar pendulum principle. The moment of inertia of an object can be measured using a measuring tool that works at the moment of the inertia oscillation method. The bifilar pendulum experiment consists of an object which is tied on either side by a rope and then attached to a support. Objects are deviated horizontally with a small angle to the equilibrium position and then released, the object will experience periodic oscillations. Based on the experimental results the shorter the distance of the two b...

Introduction The time period of a pendulum is related to its length, the longer the pendulum the longer is the time period, however you might not know that the period is also related to the gravity. If you took a pendulum to the moon, it would swing more slowly so have a longer time period. In this experiment I will measure the acceleration due to gravity on earth by measuring the time period of a pendulum

Vibrations in Physical Systems, 2018

Dynamics of the nonlinear spring pendulum is analysed using two asymptotic approaches. The multiple scale method is commonly applied with using two time scales. The purpose of the research is to justify the introduction of an additional third scale. Results of the analysis clearly show that introducing the third scale improve correctness of the approximate analytical solution. The obtained results allow for qualitative and quantitative analysis of the behavior of the studied system with a high accuracy. Calculations are made both in the neighbourhood of the resonance and also far from it.

Journal of Computers in Education, 2015

Traditional physics labs in high school suffer from slow data acquisition so that some dynamic behavior of variables could be hidden from students. Modern electronic devices such as Lego Mindstorms NXT, smartphones and Arduino can acquire data at a fast rate and can be used to measure dynamic variables with reasonable precision in physics experiments. A case in point is the changing angle of a pendulum experiment. With a tool called InduLab, students in three groups using the mobile devices mentioned above in pendulum experiments collected data and built their models with the data. Experimental results showed that the Arduino group achieved the highest success rate of building correct models, followed by the smartphone group and then the NXT group. The results indicate that modern lowcost electronic devices can be used to improve physics labs in high school.

The purpose of this laboratory experiment is to study ballistic pendulum, especially to use the principle of Conservation of Momentum and Energy on the example of collisions. In this lab particular examples were done. For instant, in the 1 st part: there was a collision between pendulum and ball, which were explained by conservation of momentum theory. While, in the 2 nd part: ball and block of pendulum were swinging up, which is can be explained by theory of conservation of energy. However, due to some hypothesis that was predicted during lab the results cannot consider as true value.

Polymer Testing, 2006

The complex elastic modulus, or its real component and the internal friction, are the mechanical variables that characterize the dynamic behaviour of linear viscoelastic materials. Free or forced oscillations produced by inverted torsion pendulums or rheometers are usually used to measure these variables. Linearity is checked sometimes by recording the stress vs. strain curve, otherwise by measuring whether the internal friction or any component of the dynamic modulus is independent of the strain amplitude. This paper demonstrates that the linear dynamic response of viscoelastic materials cannot be assured just by looking at the stress-strain amplitude detected by forced oscillation torsion devices. Furthermore, it is shown that internal friction measured at the resonance frequency of the experimental device provides an extremely accurate tool to determine the presence of nonlinear mechanical effects. This issue is shown for polycarbonate samples submitted to forced oscillations in a torsion pendulum working at resonance.