A V-shaped wooden base is constructed so that the point of the V is lower than the open end, as seen in the photographs below. When a wooden cylinder is placed at the center of the V and released, it rolls downward, toward the point of the V, as seen in an mpeg video by clicking your mouse on the photograph at the left.

  

 

A double cone is then positioned at the center of the V. When it is released, will it:

 

• (a) roll toward the point of the V?
• (b) roll toward the open end of the V?
• (c) remain where it was released?

 

After May 2, 2014, click Read More for the Answer

The answer is (b): the cone will roll toward the open end of the V, seeming to defy gravity, as seen on an mpeg video by clicking your mouse on the photograph below.

 
In fact, the cone is not moving upward. Because of the angle of the cones and the geometry of the track, the center of mass of the double cone actually moves down as the cone appears to roll uphill.