Demos: 1J-24 Climbing Double Cone
Viewed form the side, a rolling double cone appears to defy gravity and roll uphill. Upon inspection, it is seen that because the ramp widens, the CG of the double-cone actually drops and is, in fact, rolling downhill.
Directions: Make sure the cone is centered at the bottom (apex) of the ramp. Release it and it will roll slowly toward the other end.
Suggestions for Presentation: Focus on the fact that the ramp does indeed slope upward. If the ramp stays flat on the table, students will not be able to see that it also flares from the lower end. Then ask if they would expect the object to roll up the ramp on its own, without assistance.
Applications: None that are evident.