Collisions II Exercise 1: Magnet-Magnet Collision – Total
Collisions II
This week we are continuing to explore different types of collisions. However, we will take a more quantitative approach to our analysis this week and look at both momentum and kinetic energy.
Exercise 1: Magnet-Magnet Collision – Total
1.1 Open the capstone file “Collisions 2” on the computer desktop. As with the previous collision lab, you will need to consider the following:
a) The sensors are set up for you in Capstone, but you will have to correct for the fact that the motion sensors have different reference frames.
b) You can “simulate” the absence of friction by tilting the track.
Refer back to Collisions I if you forget how to setup your station.
Test that your system is set up properly by collecting a data set from a single-single cart collision (magnet-to-magnet) where one of the carts is originally at rest. Is it as you expected?
1.2 Use the Capstone calculator to create functions which calculate the momentum of cart 1, the momentum of cart 2 and the total momentum of the two-cart system. Keep in mind:
a) For clarity, it would be best to call the momentum variables “p1”, “p2” and “p”, respectively.
b) When defining the function, make sure to use the variable name (you can find them by clicking the rainbow triangle 
– e.g. Velocity Ch P2). This is the same way you would reference p1 and p2. You will need to input the actual mass of the carts into the equations. The masses are written on each cart.
c) Use the variable name rather than the run number when building your equation.
Once the momentums are defined in the calculator, they will appear in your Data Summary list. Use Capstone to plot the system momentums as a function of time (add all three to your plot).
1.3 Use the calculator again to create new functions which calculate the kinetic energy of cart 1, the kinetic energy of cart 2 and the total kinetic energy of the two-cart system. (Don’t forget to label the energy functions “K1”, “K2” and “K”, use the variable name not the run number, and finish with the ACCEPT button.) Use Capstone to plot the system kinetic energies as a function of time. (You can add a second plot area to the Capstone screen with the ‘Add a New Plot Area to the Display’ button – this way you can see the momentum plots above the kinetic energy plots).
1.4 In your notebook, sketch the relevant section of the system momentum and kinetic energy graphs as a function of time, one underneath the other with their time axes aligned. Annotate and comment on any features of your graph which are important.