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Center of Gravity at Work:
A Wheel and a Double Cone Climb Up an Incline by Themselves

A Wheel and a Double Cone Climb Up an Inclined Plane by Themselves

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  • More Information About This Video

    A Wheel and a Double Cone Climb Up an Inclined Plane by Themselves

    The objective of this video is to demonstrate that the center of gravity of objects always tends to the lowest point possible in order to reach rest.

    Introduction

    Everybody knows that an object tends to roll down an inclined plane, with increased speed if friction or other conditions allow this, because the force of Earth gravitation is applied to the object and pulls it downwards to the lowest point possible.

    But can an object, without any external or internal source of energy, climb up an inclined plane by itself?

    A Double Cone Is Climbing Up Inclined Rails by Itself

    In our first demonstration, surprisingly, a double cone climbs up diverging inclined rails.

    A Double Cone Is Climbing Up Inclined Rails by Itself

    This happens because the diverging structure enables the center of gravity of the double cone to go down whereas at the same time the double cone itself climbs up the rails. In this case the center of gravity of the double cone is lowered more by the diverging structure than it is raised by the climbing process.

    This could be demonstrated if we measure the height of the double cone's axis at the lower end of the inclined rails and compare it to the height at the upper end, then we will see that the height at the upper position is smaller.

    Note that in order to achieve the climbing effect the experiment must be set up correctly because there is a tradeoff between the divergence angle of the rails, inclination of the rails and the cone's angle.

    In 1694, this experiment was mentioned by William Leybourn (an English mathematician and land surveyor) in one of his books calling this device the Uphill Roller.

    A nice link with further explanations and calculations: Defying gravity: The uphill roller

    A Wheel Climbing Up an Inclined Plane by Itself

    In our second demonstration a wheel climbs up an inclined plane. This is possible because a relatively heavy small object (a heavy magnet in our case) is attached to the rim of the wheel. Now the center of gravity of the wheel is very much close to the heavy object and not located at the middle of the wheel as it was before at normal conditions.

    A Wheel Climbing Up an Inclined Plane by Itself

    When the wheel is placed on the lower end of the inclined plane with the small heavy object placed in the position as seen in the image above, the wheel begins to turn and rolls up the inclined plane because its center of gravity has the possibility to move downwards (because of the force of gravity) by rolling the wheel upwards at the same time. In this case, also, by climbing the plane the wheel's center of gravity goes more down than the ascending process takes it up.

    At the start position the heavy object is placed, by us, a little bit lower than the highest position possible (in order to enable rotation in the ascending direction) but at the end position, when the wheel comes to rest after moving back and forth for a while, the heavy object reaches its lowest point possible somewhere near the surface of the inclined plane.

    Note that in order to achieve a good climbing effect the object has to be attached close, as much as possible, to the rim of the wheel and must be quite small and heavy enough relatively to the wheel size and weight in order to be able to rotate it.

    To sum up:

    Because of the unique structure, while the wheel or the double cone climb up and rise along the incline, the center of weight is falling in the same time because the center of gravity of objects always tends to the lowest point possible in order to reach rest (equilibrium).

    This happens because the force exerted by Earth gravity on an object pulls it down and as a matter of fact the weight property of an object is the force applied by gravity on the object. Although we sometimes might be confounded by gravity as happened with the demonstrations shown above, gravity is not.

    Center of gravity definition: The center of gravity is an imaginary point in a physical object where the total weight of the object may be thought to be concentrated - instrumental for certain physics calculations like in designing structures or in predicting the behavior of moving bodies.

    Note that from a practical point of view, on earth surface, the center of mass and the center of gravity are the same for most applications and calculations.





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    Last updated: October 2012
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