Lab 7: Two- Dimensional Collisions University of Michigan Physics Department Mechanics and Sound Intro Labs

You have now seen the laws of conservation of momentum and energy in action in one-dimensional collisions, and you have begun to explore rotational motion. Now it is time for you to apply these concepts to a two-dimensional situation.  Much of the equipment in this lab is the same as in Lab 4. You will use the same air-table and webcam set up. Webcam

Two-dimensional collisions of extended objects are more complicated than their one-dimensional counterparts, but they can be analyzed in the same manner that you analyzed projectile motion earlier. That is, you can break the motion into its ‘x’ and ‘y’ components and study each component separately. You can then analyze your data and gain some insight into the workings of two-dimensional collisions.  You will use the same air pucks as in Lab 4. You have also been provided with Velcro edged pucks to study inelastic collisions.

You first saw the equipment that you will use in this lab in your study of projectile motion (Lab 4). The air table again provides a nearly frictionless, two-dimensional environment in which to study motion. You will use the same video capture technique that you used in Lab 4. You will be observing elastic and inelastic collisions, and some interesting phenomena. You will also be asked to look at the motion from the center of mass reference frame of the colliding system. Consult your lab manual for a discussion of reference frames and the center of mass.  The impact parameter causes some interesting motion in collisions. Examining motion in the center of mass reference frame can ease these calculations.

You will need to add your own columns in LoggerPro ® for this analysis, and it is important that you work efficiently. To add a column in LoggerPro ®, click on the ‘data’ toolbar and select ‘New Calculated Column’. You will need to name your column and specify its units, as well as enter the calculation that must be performed. To add a column from your collected data, click the ‘variables’ button at the bottom of the window. You can specify addition, subtraction, multiplication, and division using the corresponding symbols on the keyboard, and the standard order of operations is observed. Using these tools, you can analyze and interpret your results.  The `New Calculated Column’ menu. You will become very proficient at adding your own calculated columns in this lab.

Once you have finished this lab, you will have a better understanding of collisions in two dimensions, and you will have seen that the conservation laws are observed in more than one dimension as well. You will also have seen a connection to rotational motion, which you will resume your studies of next week.