Day 67: Modified AtwoodPosted: December 16, 2013
A more dynamic view of this collage is available here.
Today we were working on a problem (#4 in Practice 3 in here) and I wanted to investigate the situation a bit more closely. The problem is a modified atwood, and I had one set up with a wireless force detector on a cart, so the situation was different than the problem in that it was essentially frictionless. I showed students what the F vs. t graph looked like when I just held the cart (a horizontal graph, as F is constant). Then I asked them what would happen to that graph if I released the cart. The above is what they drew, below is what actually happens.
After taking the above data students discussed why this occurs using qualitative free body diagrams of the hanging mass before and after the release.