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10 votes
1 answer
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Equations for an algebraic gömböc

A gömböc is a $3$-dimensional convex body (having uniform density) which has exactly one stable and one instable equilbrium position (see https://en.wikipedia.org/wiki/G%C3%B6mb%C3%B6c). Such a convex ...
Roland Bacher's user avatar
9 votes
2 answers
379 views

Which convex bodies roll straight?

Let $K$ be a convex body in $\mathbb{R}^3$. Suppose $K$ is held at some position and orientation on an inclined plane, and released. Let there be sufficient friction so that it rolls without slippage. ...
Joseph O'Rourke's user avatar
6 votes
0 answers
237 views

Generalization of the non-existence of a monostatic planar body

Domokos, Papadopulos, and Ruina showed that there does not exist a convex planar rigid body of uniform density which has only one orientation of stable equilibrium and one orientation of unstable ...
Yoav Kallus's user avatar
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4 votes
0 answers
158 views

On moments of inertia of planar and 3D convex bodies

The following observation can be readily proved using the perpendicular axes theorem and intermediate value theorem: "Given any planar figure C, through any point on it, there is at least one ...
Nandakumar R's user avatar
  • 5,979