A small puck of mass 0.40 kg is tethered to a post by a light string and moves in a circular path on a frictionless tabletop. The puck has an initial speed of 4.0 m/s and revolves with an initial radius of 1.0 m. A physics student carefully pulls the string through the center post, decreasing the radius to 0.60 m and increasing the puck's speed. Determine the work done by the student. Verify that the work-energy theorem is satisfied by this action.