Physics I Lab

PH111L - Physics I Lab

Fall 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 Th & 4:20 PM - 5:15 PM M T Th F

The last series of experiments, entitled "Conservation of Linear Momentum" (a description of which can be found in the lab manual beginning on page 87), will be performed in BL113 during the next two weeks.

The lab reports for the "Conservation of Linear Momentum" experiments are due in the green bin outside my office by 5:30 PM, one week after you performed them in the lab.

Section 52 will meet at 8:05 AM on Monday, Nov. 10.

Section 53 will meet at 8:05 AM on Friday, Nov. 7.

For this experiment, there are two tasks: 1) Determine if linear momentum was conserved for two different collision arrangements; and 2) Determine the type of collision for the case where the carts do not stick together. The two arrangements should have one where the carts bounce off and one where the carts stick together after the collision. Perform a levelness test and determine the acceleration of the track with a collision between the carts. Remember to do all of the curve fits in Logger Pro. Use only the position vs. time graphs, not the velocity vs. time graphs for your calculations. Include, at a minimum, three graphs: one levelness test (placed in the Analysis section), one sample data graph with NO curve fits on it showing both carts (placed in the Procedure section), and one sample graph showing at least one curve fit on each cart (placed in the Analysis section). Do NOT average all of the trials together because they are not the same. The uncertainty in the mass should be estimated and the uncertainty in the velocity should be determined by Logger Pro as the uncertainty of the slopes of your line fits. Remember to propagate the uncertainties through all of your calculations for the momentum before the collision and after. If the two values overlap within experimental uncertainty, then momentum was conserved. If they do not overlap, then momentum was not conserved. In the analysis section, be sure that you list explicitly the values you obtained from each data file. You do not need to show how you got each one, but you must list all of the values that you used.

The coefficient of restitution and percentage change, while instructive are NOT required, they are optional for you. However, for the arrangement where the carts bounce off each other after the collision, choose one trial and determine if kinetic energy was conserved or not. Compute the total kinetic energy before the collision (with uncertainty!) and compare it to the total kinetic energy after the collision. If they are the same within uncertainty, then kinetic energy was conserved and you had an elastic collision. If not, then you had an inelastic collision.

The lab reports for the "The Simple Pendulum" experiments are due in the green bin outside my office by 5:30 PM, one week after you performed them in the lab.

Section 52 lab reports are due Monday, November 3, 2014

Section 53 lab reports are due Friday, November 7, 2014

The description for The Simple Pendulum:

For this experiment, the purposes are to evaluate the model for the period of motion of a simple pendulum and determine if mechanical energy was conserved in one of your experiments. Include one sample graph of θ vs. t in your procedure section and include a graph of θ vs. t with a sine curve fit in your analysis section. Unlike the procedure described in the lab manual, I think it is much easier to analyze the data using the sine curve fit. In Logger Pro, the A coefficient is θmax and B is the angular frequency. To find your experimental period from the curve fit, T = 2*π/B. Make a comparison between the theoretical period and the experimental period, using a format that you decide is best and make a conclusion about the appropriateness of the model for your situation. Evaluate the conservation of mechanical energy for one of your data sets (at a minimum) and calculate the energy lost per cycle for one of your data sets (at a minimum). Remember that the ω_max (in the maximum kinetic energy term) is equal to A*B, not just B! Make sure to include experimental uncertainty in your period and energy calculations and energy lost per cycle.

Download the elliptical table to your desktop

Open the file and copy and paste the two columns into a new window of Logger Pro. Once you paste the columns into Logger Pro, you can use the Interpolate function under the Analyze button to determine the values of the elliptical function for any angle used in your experiment.

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 November 07, 2014 by Galen C. Duree Jr.