The other day in class we were talking about something having to do with weighted averages1. As a familiar example of weighted averages, I had people calculate a weighted GPA for warmup (with weights given by credit hours). While we were discussing this calculation, I mentioned that I think GPAs are wack and we shouldn't use them, but that I wasn't going to get on my soapbox about this. So then a student asked about this on my daily exit quiz: The center of mass of a system of point masses in...
