Kinematics in 2D Using Videos

Use the Tracker Software to analyze Projectile Motion in 2-Dimensions.

Take a video in which one of the members of your group throws a small object (projectile).  The throw should be in a plane perpendiuclar to the line-of-sight from the camera.  There should be something fixed at the same distance from the camera as the projectile, so you can calibrate the distance.  The camera should be tilted so that up in the image is up in real life.

Suggested Tasks and Procedures

1. Describe what was thrown and what was used as the distance calibrator.  Include a screen-shot from your video.
2. Load the video into Tracker, calibrate the scale and add an axis.  Is your y-axis aligned with the up direction?  Where did you choose your origin?
3. Click Track and add a Point mass.  Frame by frame, press shift while you click the mouse button to add position-time measurements for the frames in which the projectile was in the air.  Include a screenshot of the trajectory with the positions from each frame marked.
4. Make plots of the following, and include them in your presentation:
   • x vs t
   • y vs t
   • v_x vs t
   • v_y vs t
5. In each of the above plots, also double-click to do a data analysis and curve fit to a straight line.  Comment on the slope, A, and the y-intercept, B, for each graph.  If you hover over the fit parameter values with your mouse, it will show you the uncertainty each fit parameter.  Does one of the fit parameters correspond to the acceleration due to gravity 9.8 m/s²?  If so, is the difference between this parameter and 9.8 m/s² less than the uncertainty?