Today was a great day in AP C! After a vibrant reading notes discussion students worked in pairs on a “5 Minute POGIL” that actually took about 15-20 minutes where students followed instructions to draw a force diagram for an object at rest on a ramp, split the force of gravity into components parallel to and perpendicular to the ramp (our first time doing this), proving the values of the angles in the triangle, and then using it to calculate values for the Normal Force and Friction. This came up in the textbook, but without a full treatment. It was fun to see students wrestle with the ideas involved and get to a point where they understood it. I structured the POGIL in a way where the instructions told them the outcomes of what they needed to do, but not exactly how to do it.
After the POGIL, students solved two “mini-challenge labs.” The first was to find the amount of weight (suspended inside a box) that must be hung from a pulley to keep a cart at rest on a track inclined at a specific angle (see picture below). The second challenge to determine the angle at which a ramp must be inclined in order for a weight of known mass to keep a cart from moving up or down the ramp, when connected by a string (not shown). Inclined plane problems were difficult for this class in general last year, I’m hopeful that the discovery aspect of today’s lesson will engender deeper understanding of the available tools that can be used to analyze these types of situations.
Randall Physics 