We went over problems from the second lecture test, the lab midterm, and the homework that was due.

We discussed the (restoring) force of a spring.

We continued discussing springs and derived the potential energy of a spring. We went over a problem involving the potential energy of springs being converted into other forms of energy (first kinetic, then thermal).

We discussed the forces involved when one block was sitting on top of another. We then considered a "block" of water within a larger body of still water. We used it to derive Archimedes' prinicple -- that there is a buoyant force equal to the "weight of the water displaced." Along the way we introduced the concepts of pressure and mass density.