As I explained in the last post, today was all about gathering data for the impulse-momentum experiment. Here are two short video clips that show how we set-up the equipment:
The initial momentum was varied by having different initial velocities and also by adding mass. I like having two slightly different experiments. The impulse – change in momentum graphs obtained all have a slope that should be approximately 1.0. The part with just the cart alone has a negative impulse and negative change in momentum, but the one with the rubber band has a positive impulse and positive change in momentum. Makes for an interesting discussion in the post-lab discussion.
The bulk of today was spent having the post-lab discussion for the kinetic energy experiment. The slopes were not quite 1/2 he mass for all the groups, but thankfully, all the groups did have the square relationships. We used the energy blocks again to reinforce the concept of a square relationship:
We started with a velocity of zero, so no kinetic energy. Then I said I gave the cart a velocity , v and that gave us 2 ‘blocks’ of energy. Form there, we went to a velocity of 2v, then 3v, and so on. I really like how the non-linear nature shows up using these blocks.