This year, we didn't do this as a small group activity, but as a large class discussion. After demonstrating the motion, David McIntyre asked what the potential energy graph would look like. Several students suggested things and David asked a different student to draw what they said on the board.

Of course, since this was not a small group activity, only a few students actually contributed to the discussion and only one had to draw. However, we were able to address a lot of the same points and did so in significantly less time, so doing this as a large group discussion would be one way of shortening this activity.

This year, I did this as a small whiteboard question. A few students specifically asked what they were supposed to be plotting with respect to. The wrap-up discussion was a nice place to introduce the idea of polar plots.