To obtain a close up view of this part of the data, click on the scale to fit icon, which is located in the top left hand corner of the graph window. ‘V). Measuring acceleration for MI + MM constant, with different values of MI and 1 . To obtain the value for the acceleration of another system with the same total mass, but with different values of MI and MM, increase the mass of MM, and decrease the mass of MI by a fixed amount so the mass difference is 20, 30, 40, and 50 g; the total mass should remain at egg (I. E. He mass of MM runs from 105 to 125 g in increments of 5 g, and the mass of MI runs from 95 to 75 g in increments of 5 g). For each run, the total mass of the system, MI + MM should be equal to 200 g. 2. Follow the instructions given above for each run, and record the values of the masses and the experimentally determined acceleration into the excel spreadsheet. Print out one or two typical graphs to include in your laboratory report. V). Measuring acceleration for MM – MI constant, with different values of MI and MM 1. Choose initial values of MM and MI of 45 and 35 g respectively. Run the
Record these results into a second excel spreadsheet, along with the values of MI and MM. 2. To obtain a total of five runs, increase each mass by 40 g, rerun the experiment, and record the results. The mass difference should remain the same. Thus, MI will take on values of 35, 75, 1 15, 155, and 195 g, while MM should have the values of 45, 85, 125, 165, and 205 g. VI). Analysis of the Results 1. Theory predicts that the acceleration is given by the net force divided by the total mass (see equations 4 and 5). Now, you should compare your experimentally determined acceleration with the theoretical prediction.
To determine the theoretical prediction, create three new columns in the excel spreadsheets: one for the net accelerating force (MM -MI)g, one for the total mass (MI + MM), and one for the theoretically predicted acceleration: Acceleration = (Net accelerating force)/total mass 2. Create another column for the percent difference between the experimental and theoretical values of acceleration. 3. Another way to compare experimental and theoretical results is to plot the net force FINE vs.. The experimental acceleration. Equation (5) indicates that this should e a straight line with slope equal to the total mass.
For the results obtained in part ‘V, with the total mass constant, plot FINE versus experimental acceleration, and fit the graph with a straight line. Compare the slope of the line with the actual total mass (. 200 keg). What is the percent error? Print out this graph and include it in your laboratory report. 4. Theory predicts that when the net force is constant, the acceleration will vary inversely with total mass (see equation 5). For the data obtained in part V, with the mass difference held constant, plot the experimental acceleration versus mass.
Approximate the data with a power law fit (y = c x n). Record the best fit values of c and n, and compare them with theoretical predictions based on equation 5. W). Include the Answers to These Questions in Your Laboratory Report 1 . How does the acceleration depend on the net accelerating force when the total mass is constant? 2. How does the acceleration depend on the total mass when the net force is constant? 3. What sources of experimental error most likely caused the differences you found WI) Clean up the area around you; put away the equipment and shut down the computer.
