Say I have a solid sphere of mass on a horizontal surface. If suddenly there was a spherical hole(shape of a sphere) off center, will the sphere suddenly move? And there is no friction between the ground and the sphere. I'm assuming that it will. But my reasoning is this, the sphere suddenly having lost mass will have it's CM change locations. This will make it unstable or stable depending on the location. If a hole appeared sideways, then the CM will be off centered relative to the vertical axis going through the point of contact, causing the new object to rotate forever. If the hole is on axis going through the contact point, then it will oscillate if the hole is above the original CM. The new object will not oscillate if the hole is below the CM, it will just fall and rotate in one direction forever since its unstable. Is this the correct logic?