Temple University: Gerardo Mendoza and Dan Reich's "Calculus on the Web"
Click on the "Index" for Book II. Scroll down to "2. Applications of Integration," and click button 120 (Solid of Revolution - Shells). Work on problems 5-17. If at any time a problem set seems too easy for you, feel free to move on.
Click http://cow.math.temple.edu/ link to open resource.