Can a double cone defy gravity?
Place the double cone on the lower end of the tracks and let it go.
The double cone seems to defy the gravitational force of the Earth and roll uphill.
The double cone paradox is an optical illusion, not a device that questions the laws of physics. Although the double cone appears to be rolling uphill, its centre of gravity is actually moving lower all of the time. There are three key variables at work here. The angle of the tracks in relation to one another, the angle of the tracks in relation to the horizontal plane, and the angle of the cones in relation to one another. The mutual relations of these variables determine whether the double cone will ‘roll uphill’ or not.
The first written notation about the double cone paradox and a detailed description of the experiment was included in the report written in 1694 by William Laybourn, an English land surveyor. In his report, William stated that although your senses can be deceived, the law of gravity cannot. This same logic remains true more than 300 years later.
Links
Mathematics and history of the upphill roller
