Lab 4 Motion of a Simple Pendulum Purpose: To investigate the relationship between the length and the time period of a simple pendulum and to determine acceleration due to gravity from it. Theory: A pendulum is simply a mass suspended from a pivot so that it can swing freely. When a pendulum is displaced from its resting equilibrium position, it experiences a pulling force due to gravity that will accelerate it toward the equilibrium position. When released, the gravitational force will cause it to oscillate about the equilibrium position, swinging back and forth. The time for one complete oscillation is called the time period. In this lab we will learn about the dependence of the time period on various relevant parameters. Theoretically the time period of a pendulum is related to its length as Velocity O Acceleration D Energy Graph Ruler Stopwatch Period Timer Click and drag to change amplitude Period Timer Period 0.0000 s Change length Length 1 0.1 Normal O Slow 1.00 kg Gravity 9.81 ms Earth Friction Reset Lot T = 2 Rearranging, L = g 1=9(4) g In the above expression 'T' is the time period, 'g' is acceleration of gravity, and 'L' is the length of the pendulum. A plot between 'I' and (7) will be a straight line with a slope equal to the acceleration due to gravity (remember Lab-1 and equation of a straight line!). In this virtual lab, you will write down the time periods for certain given lengths and later you will do your analysis in Microsoft excel. Procedure: Go to the following virtual physics lab website link http://phet.colorado.edu/en/simulation/pendulum-lab Click on the lab. On the next page go to the third image that says 'Lab' and click. The following picture is a screenshot of this window. You might have to update your adobe flash player and java to the latest version. Those are free and safe to install in home computers. I will recommend using either firefox or google chrome browser. 1. Try to understand the functions of various buttons. You have the option of changing the length, mass and amplitude of oscillation of the pendulum. Length and mass buttons are located in the 'dial' on the upper right corner of the window. To change the amplitude, you must first click on the pendulum bob and manually drag on either side. 2. Make sure that gravity is set at 9.81 m/s (Earth) and friction at minimum (None). 3. Click on length to select it and change length to 0.3 m. You can increase the length by clicking the triangle button on the right or decrease by clicking the triangle button on the left. Keep mass to 1 kg for the whole experiment. 4. Check the 'Period Timer' button in the lower left corner. Click on the pendulum bob and drag it to the right until the amplitude is 10. Release the bob and then click the triangular button inside the timer. Record the time period or the oscillation period for this length in the table below. | 5. Click on reset and change the length to 0.4 m. Repeat steps described in (4). Record the time period for this length in the table below. 6. Repeat the above steps for the other lengths as suggested in the table below and record the corresponding time periods. Length (m) Oscillation Period (s) 0.3 0.4 0.5 0.6 0.7 0.8 0.9 Activate Windo 0.95 Go to Settings to acti 1.0 Lab-Report Guideline Make sure to use the current lab report template. Else, you will lose some points. Write the name of the experiment. Write your full name. Abstract: In abstract you should briefly summarize the whole experiment. You need to explain the goal of the experiment, the result you find, and if the result is not up to the expectation what could be the reason behind it. If there are some relevant mathematical results, make sure to mention it. The abstract should not contain more than four or five sentences. The abstract will be graded out of six points. Theory and Procedure: You should briefly explain the theory (you can take some idea, but don't try to copy everything from the manual) and how it leads to the experimental results. You also have to briefly explain the steps that you used to collect data. This part will be graded out of 7 points. If there are numerical steps in the theory, you must briefly discuss those here. Data Analysis: This is the analysis and/or the excel analysis that you do. If there is an excel analysis part, you will upload that file separately so don't have to write anything. You can simply say "See the uploaded file". It will be graded out of 25 points. Results, Conclusions and Source of Errors: You should mention all your results here. Don't repeat the theory here again. Whatever conclusion you draw should go here. Also if there were some room for errors, you mention about it here. For example, in the pendulum lab, we ignored air friction, which is a source of error. Seven points are reserved for this part. Questions: There will be some multiple choice questions which are based on the lab. Six points for this part. Questions will be posted in the form of 'Lab Quiz on a separate folder in blackboard. Name of the Experiment: Name: Abstract: (6) Theory and Procedure: (7) Data Analysis: (25) Results, Conclusions and Source of Errors: (7) /44