Conservation of Momentum Lab

Here is the lab handout: Lab-ConservationOfMomentum.pdf

Watch this video before the class you want to do the lab:

Your Completed lab will have the following:

• Your collision image with the selections printed (Landscape is best)

• Your calculations of the momentum before and after as lowest possible, best guess and highest possible. (6 calculations)

• An argument where you cite data to show whether the range of momentum before overlaps with the momentum after

• An assessment of the sources of error (pick 2 or 3) and how you would mitigate those sources of error.

Work in groups of exactly 2. If you must be a group of 3, you need to analyze two different collisions.

Old stuff:

5:46COM Lab with Video Analysis

You might choose to do the Photogates: (Stop watching at 1:08 - after that it gets specific to IB Physics only)

2:27COM Lab with Photo Gates

Pandemic Instructions:

Video Analysis Directions (For Chromebook)

• 1. Pick a movie from the bottom of this page. AB movies are two red carts of equal size, BC is a big glider running into a small, and CB videos are a small glider running into a big.

  2. Download the movie file to your Drive by clicking the download link below. Save it to your Google Drive. (should do that automatically on a Chromebook)

  3. Go to this document <Here> and go to the link. (You must be signed into your ttsdstudents.org account)

  4. Click where is says "CHOOSE FILE" and go to where you stored it on your Google Drive and you should see a lovely video of the aforementioned Smart Water Bottle with dyed water in it. (should have used red dye...)

  5. On the left side of the video, click the little "1.0 SCALE" button. It will bring up a tool. Drag the tool so that the black scale line goes from the left to the right side of the Meter stick that is below the airtrack. (On my Chromebook this is hard to do because the shaded box covers up the top mark, but if you click back and forth between the "SCALE" and "Add" buttons you can kind of guess and check.) Type that this distance is 1.00 m in the two boxes. (1.00 in the first box, m in the second)

  6. Now click on the gear button on the lower right side of the video screen, and set it to advance 5 frames for every data point. (This is so we don't have 10 billion data points, only about 60.) Close the settings dialog box.

  7. Now choose the "ADD" button on the top left side. The cursor will become a crosshairs when is is over the video. Make sure the movie is at the beginning, and now we are ready to take data. The app will record in the data table the position x and y, as well as the time for every click you make, and then advance the video for you. It also will place a little dot on the video that becomes less and less helpful as the dots get closer together (i.e. you can't see through the dots - spoiler alert) So what I do is I line up the bottom of the crosshairs to the left side of the first moving glider.

  8. Play the movie

  9. Put the left side of the crosshairs where the water meets the left side of the red ruler and click. You will see a dot (that doesn't obscure the water level) and the video will advance. Repeat until you have advanced through the entire video. (about 60 dots) You can see the data going into the table on the right, and you can see the graph of your data. Only the blue y values are important.

  10. When you are done clicking, go over to the data table on the right side, and tap the header with two fingers, or do an Alt-tap on the header. (Your Chromebook settings may be different from mine). A menu will pop up, choose "Copy". Go to your Google Drive, and paste the data into a new Google Sheet. (Click in cell A2, and type ctl-V to paste). Label column A "TIme (s)". (Type "Time (s)" into call A1) and column C "y (cm)" and column E "Vy (cm/s)" Delete columns B and D (X and Vx).

Mass Data for Pandemic:

Glider A: 300.0 +/- 0.05 g

Glider B: 291.2 +/- 0.05 g

Glider C: 143.4 +/- 0.05 g

(We will neglect the uncertainty of the masses because it is so small)