Hi, A sphere and a cube full at 99.99% with water are put in symetrical position to the center C. Sphere at right and cube at left for example. When they turn together at the center C, the centripetal forces are not the same. The cube has not water all around faces, especially the face closed to the center C and this face can't put pressure (we arrange the shape for that). The sphere can put pressure in the direction of the center even the sphere is at 99.99% with water. Example: R=100m side of cube = 1m Radius of sphere = 0.62 m Volume of sphere = volume of cube = 1m Mass of sphere = mass of cube = 1000 kg Rotational speed = 10rd/s For the cube F=1000*100*100.5 = 10.05 e+6 N For the sphere F=1000*100*(100.3-99.7) = 60000N Is this result is correct ? Or if not have you the method ? Edit: we can turn or make oscillation +/- 30 ° around, but this create a force and I think the result is not good but why ?