Mechanics: Double Cone

PIRA Class: 1J11.50

Purpose:
A surprising behavior illustrating the importance of tracking an object's center of mass.

Description: 

Place the double cone at the "bottom" of the ramp and let go. The double cone will roll unaided to "top" of the ramp. The double cone appears to roll uphill, however a careful view of the axel shows that the CM is actually moving downward. In the figure, the cone rolls left to right as the CM moves downward from blue dashed line to the red dashed line.

Students can make their own double cone using two Styrofoam cups and a track of metal rods or wooden dowels with one end raised slightly. [New Versions of the Rolling Double Cone]

Equipment:
Double cone and track

Location:
Shelf 122