PH112L - Physics II Lab

Winter Term 2014

General Information

Instructor:    Galen C. Duree Jr., PhD

Office:    Room DL102                       Phone:    872-6025                                 Box:    182


Office Hours:      9:30 AM - 11:00 AM   T F  &  4:20 PM - 5:15 PM M  F

The first series of experiments for the Physics II labs were conducted in BL114 last week and earlier this week.

The title of the experiments performed was "Angular Acceleration and Moment of Inertia".  A description of the procedure in given in the lab manual, beginning on page 95.  The lab reports are due in the green bin outside my office by 5:30 PM on the dates listed below:

Section 61 lab reports are due on Tuesday, Jan. 6.

Section 58 lab reports are due on Friday, Dec. 19.

For this lab, you are to determine the rotational inertia of a plate and the torque caused by friction, using only the first method described in the lab manual (varying the hanging mass).  Use the position vs. time data for your analysis and make sure that you list the filename and the data that you get from each file in the Analysis Section.  Be sure to include at least three graphs in your report.  The first graph should be a sample graph of theta vs. time for one of your trials, without curve fits.  This graph should appear in the Procedure Section.  The second graph should be a sample graph of theta vs. time with a curve fit, showing the fit parameters with uncertainty and the fit interval used.  This graph should appear in the Analysis Section.  The third graph (also placed in the Analysis Section) should be a graph you make showing the angular acceleration of the plate (NOT the rotary motion sensor!) vs. mass.  This graph should have a fit line on it showing the fit parameters with their uncertainty in the line.  Please make sure that you show the equation of the fit line on the graph.

If you would like to work on some extra credit, you can do the experiments for calculating the rotational inertia of the plate and torque on the plate by varying the radius.  This is the second method listed in the lab manual and is NOT required.  If you do this activity, please include a graph  in the Analysis Section showing the angular acceleration of the plate (NOT the rotary motion sensor!) vs. radius of the pulleys attached to the plate.  This graph should also show a fit line with the equation of the line and the uncertainties.

You can also earn extra credit if you evaluate the model used to calculate the rotational inertia and torque due to friction.

When calculating the rotational inertia and torque due to friction, make sure that you propagate the uncertainties!


Download a copy of the Error Analysis Worksheet


Lab Report Format

A complete lab report must have the following sections:

Do not forget to update your Table of Contents and to number the pages in your lab notebook!

The first page of your report must have a title, the name of the P.I. (explicitly indicate who was the P.I.), the name of the lab assistant, and the date that the report was turned in (not the date that you performed the experiment!).

*Abstract - a BRIEF description of what you were investigating, how you conducted the experiment and your conclusions based on your experience.  The abstract should not be a discussion of what you are going to do in the lab.  The abstract cannot be written before you have analyzed your data.  In the lab notebook, skip a page or two so that you can write this in at the beginning of the report after you have analyzed your data.

Introduction - a discussion about any details that you think would help someone perform the experiment.  This should include a discussion about the model (equations that you are using) or the method selected for performing the tests.  If you use models (equations) in your analysis, list the models in this section and describe what each of the variables represent.

**Procedure - a detailed description of what you did in the lab.  At the beginning of this section, place the date and the time that you began the experiment.  This section must include a schematic, detailing how things were connected, where appropriate.  The raw data must appear in this section immediately following the description about how the data was taken.   A person must be able to read your procedure section and be able to duplicate your results without having the lab manual present.  Do not do any calculations in this section, just record how you performed the experiments and record the raw data.  If the data is taken by computer, you must specify the path and filename where the data is stored.   This information must be listed in this section right after the description of how the data was taken.  Do not simply list all of the files generated at the end of the section.

This section MUST be signed by the instructor before you leave the lab.  If you turn in a report without the signature, it will not be accepted!

Analysis - a sample of the calculations made in the lab.  This section should include a sample of the error calculations and propagation of errors used in your analysis.   The final data that you are analyzing to generate conclusions, the values with appropriate uncertainties, must be shown in this section.  The actual calculations for each one does not have to be included, as long as you show an example for one, but you may include them all if you wish.  The calculations may be done by the computer, but include printouts of the worksheet in your lab book.  Any graphs or printouts that are placed in your notebook must occupy one whole page and be trimmed to fit within the page and not hang outside of the notebook.

*Conclusion - this section must have a conclusion that is based on your experiments and analysis.  If your conclusions do not following logically from your analysis, your grade will be deducted significantly.  This section must also contain a brief description of significant factors that you think affected your data, in particular, the uncertainties in your data (factors that contributed to the error in your experiment).  A good thing to keep in mind is to think of this report as a report you are submitting as part of your job responsibilities.   If you do not think your boss would accept what you have to say, it is a safe bet that I will not like it either.

The asterisks indicate the sections that I will pay closest attention to.

Modified December 15, 2014 by Galen C. Duree Jr.