# JiTT using Physlets: Upper Division Mechanics

Most of these preflights and the Physlet examples that are incorporated into them are reasonably self-explanatory. Only two examples (explained briefly below) are non-Physlet-based with a Physlet followup activity planned for the in-class time. In a number of cases, however, student submissions warranted revisiting the Physlet simulation in class, or having the students revisit the simulation in their own out-of-class time to clear up any lingering problems.

## Preflight #8 (Phase Diagram, Plane Pendulum)

Preflight #8

This is a non-Physlet-based preflight with an intentionally planned Physlet in-class followup activity. Most of these students had not seen a phase diagram before, and if they had, they really hadn't grasped it. We made a class activity out of working through the plane pendulum's phase diagram, giving the pendulum differing amounts of energy and observing the resulting phase diagram. (The students traced each phase space curve on the whiteboard as it was drawn out by the physlet, and when we were done with the class activity, we had essentially duplicated the salient features of the static textbook figure as shown in preflight question #1.) The combination of the "explain the textbook figure" followed up by the in-class Physlet-based activity worked very well. Note: click the "In-class Physlet activity" link on the preflight page to get to the in-class activity.

## Preflight #9 (Calculus of Variations; Eulers Equation)

Preflight #9

This is another non-Physlet-based preflight with an intentionally planned Physlet in-class followup activity. The brachistochrone was a topic that very much interested but perplexed the students. Being able to see that the brachistochrone path is traced out by a "spot" on the rolling yellow ball in the Physlet simulation seemed to really help the students visualize and understand the brachistochrone. The notes at the bottom of the Physlet page helped the students work through some of the details, and some students did followup extra credit work with this simulation. Note: click the "In-class Physlet activity" link on the preflight page to get to the in-class activity.