This student activity is designed to help upper division undergraduate students work with central forces in classical mechanics. A hockey puck is tethered to the center of an air-hockey table, and the students observe the motion of the hockey puck, allowing them to observe the effects of central forces on the puck. Students are asked to plot the potential energy graph of the hockey puck. An instructor's guide is available to help guide the activity along with the student handout.

This material is part of the Paradigms in Physics project at Oregon State University. This work promotes the use of active student learning in upper division physics courses. Both learning materials and learning strategies are provided to help both students and instructors.