
determination of acceleration due to gravity by compound pendulum
Sep 9, 2023
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The experiment was conducted in a laboratory indoors. We repeated this measurement five times. << gravity by means of a compound pendulum. How to Calculate Acceleration Due to Gravity Using a Pendulum This page titled 15.5: Pendulums is shared under a CC BY 4.0 license and was authored, remixed, and/or curated by OpenStax via source content that was edited to the style and standards of the LibreTexts platform; a detailed edit history is available upon request. /F1 6 0 R This is consistent with the fact that our measured periods are systematically higher. Click on the lower end of the pendulum, drag it to one side through a small angle and release it. 27: Guidelines for lab related activities, Book: Introductory Physics - Building Models to Describe Our World (Martin et al. In order to minimize the uncertainty in the period, we measured the time for the pendulum to make \(20\) oscillations, and divided that time by \(20\). Your email address will not be published. We are asked to find the torsion constant of the string. The force providing the restoring torque is the component of the weight of the pendulum bob that acts along the arc length. To perform a first-hand investigation using simple pendulum motion to determine a value of acceleration due to the Earthsgravity (g). Objective /MediaBox [0 0 612 792] In this experiment, we measured \(g=(7.65\pm 0.378)\text{m/s}^{2}\). (ii) To determine radius of gyration about an axis through the center of gravity for the compound pendulum. The Kater's pendulum used in the instructional laboratories is diagramed below and its adjustments are described in the Setting It Up section. The various results that I have found, reveals that the average value of acceleration due to gravity for Azare area of Katagum Local Government is 9.95m/s 2 which approximately equal to the accepted value of 10.0m/s 2. Like the force constant of the system of a block and a spring, the larger the torsion constant, the shorter the period. Our final measured value of \(g\) is \((7.65\pm 0.378)\text{m/s}^{2}\). PDF Experiment 9: Compound Pendulum - GitHub Pages Solved 1. In an experiment to determine the acceleration due - Chegg Set up the apparatus as shown in the diagram: Measure the effective length of the pendulum from the top of the string to the center of the mass bob. The object oscillates about a point O. To determine the acceleration due to gravity 'g' by using bar pendulumBar PendulumBar Pendulum ExperimentCompound Pendulum ExperimentAcceleration due to grav. >> In this experiment the value of g, acceleration due gravity by means of compound pendulum is obtained and it is 988.384 cm per sec 2 with an error of 0.752%. This method for determining g can be very accurate, which is why length and period are given to five digits in this example. In the experiment the acceleration due to gravity was measured using the rigid pendulum method. Performing the simulation: Suspend the pendulum in the first hole by choosing the length 5 cm on the length slider. The period of a pendulum (T) is related to the length of the string of the pendulum (L) by the equation:T = 2(L/g). Such as- Newton's ring ,The specific rotation of sugar solution ,Compound pendulum, . PDF Acceleration due to gravity 'g' by Bar Pendulum - Home Page of Dr << We first need to find the moment of inertia of the beam. In the experiment, the bar was pivoted at a distanice of Sem from the centre of gravity. Each pendulum hovers 2 cm above the floor. For example, it's hard to estimate where exactly the center of the mass is. A physical pendulum with two adjustable knife edges for an accurate determination of "g". By adding a second knife-edge pivot and two adjustable masses to the physical pendulum described in the Physical Pendulum demo, the value of g can be determined to 0.2% precision. See Full PDF The mass of the string is assumed to be negligible as compared to the mass of the bob. /F9 30 0 R Surprisingly, the size of the swing does not have much effect on the time per swing . The minus sign is the result of the restoring force acting in the opposite direction of the increasing angle. 4 0 obj The results showed that the value of acceleration due to gravity "g" is not constant; it varies from place to place. As with simple harmonic oscillators, the period T T for a pendulum is nearly independent of amplitude, especially if is less than about 15 15. endobj Object: To determine the acceleration due to gravity (g) by means of a compound pendulum. Kater's pendulum, shown in Fig. Legal. There are many way of measuring this gravity acceleration, but the experiment of compound pendulum is the easiest and effective among them. Use the moment of inertia to solve for the length L: $$\begin{split} T & = 2 \pi \sqrt{\frac{I}{mgL}} = 2 \pi \sqrt{\frac{\frac{1}{3} ML^{2}}{MgL}} = 2 \pi \sqrt{\frac{L}{3g}}; \\ L & = 3g \left(\dfrac{T}{2 \pi}\right)^{2} = 3 (9.8\; m/s^{2}) \left(\dfrac{2\; s}{2 \pi}\right)^{2} = 2.98\; m \ldotp \end{split}$$, This length L is from the center of mass to the axis of rotation, which is half the length of the pendulum. We transcribed the measurements from the cell-phone into a Jupyter Notebook. The rod is displaced 10 from the equilibrium position and released from rest. PDF Measurement of acceleration due to gravity (g) by a compound pendulum PDF Mechanics Determination of the acceleration due to gravity Simple and Variables . 1 Pre-lab: A student should read the lab manual and have a clear idea about the objective, time frame, and outcomes of the lab. In this channel you will get easy ideas about Physics Practical Classes. The magnitude of the torque is equal to the length of the radius arm times the tangential component of the force applied, |\(\tau\)| = rFsin\(\theta\). size of swing . Substitute each set of period (T) and length (L) from the test data table into the equation, and calculate g. So in this case for four data sets, you will get 4 values of g. Then take an average value of the four g values found. Two knife-edge pivot points and two adjustable masses are positioned on the rod so that the period of swing is the same from either edge. Accessibility StatementFor more information contact us atinfo@libretexts.org. A . The value of g for Cambridge MA is 9.8038 m/s2.Alternatively, one can set up a photogate and time the period of a swing with a laboratory frequency counter. A physical pendulum with two adjustable knife edges for an accurate determination of "g". https://alllabexperiments.com/phy_pract_files/mech/, https://www.youtube.com/watch?v=RVDTgyj3wfw, https://www.youtube.com/watch?v=7vUer4JwC5w&t=3s, V-I Characteristics of Diode, LED, and Zener diode lab manual. The acceleration of gravity decreases as the observation point is taken deeper beneath the surface of the Earth, but it's not the location of the compound pendulum that's responsible for the decrease. If this experiment could be redone, measuring \(10\) oscillations of the pendulum, rather than \(20\) oscillations, could provide a more precise value of \(g\). The net torque is equal to the moment of inertia times the angular acceleration: \[\begin{split} I \frac{d^{2} \theta}{dt^{2}} & = - \kappa \theta; \\ \frac{d^{2} \theta}{dt^{2}} & = - \frac{\kappa}{I} \theta \ldotp \end{split}\], This equation says that the second time derivative of the position (in this case, the angle) equals a negative constant times the position. We thus expect that we should be able to measure \(g\) with a relative uncertainty of the order of \(1\)%. The uncertainty is given by half of the smallest division of the ruler that we used. THE RADIUS OF GYRATION AND ACCELERATION DUE TO GRAVITY - ResearchGate To Determine The Value of g Acceleration due to gravity by means of a The period is completely independent of other factors, such as mass. We also acknowledge previous National Science Foundation support under grant numbers 1246120, 1525057, and 1413739.