Bowling ball: spoiler
Q: ??? Given the positions of the finger holes in a (spherical) wooden bowling ball, can we embed lumps of lead to make the ball fair? How unique is this solution?
"Fair" presumably means at least that
- the centre of mass is at the centre of the sphere;
- the moment of inertia is independent of the axis we choose.
Is this sufficient? Can we do even this?
In the 2D case is condition 1 enough?
TB, 24 Jan 2002
A: Condition 1: If we can find the vertices of a tetrahedron containing the centre of the ball, then we can move the centre of mass to the centre of the ball by embedding masses at these vertices.