If half of a sphere rotating around a vertical axis, with the radian/second speed. A touch on the skin of the object.The tank and the tank, if the skin is still relative to each of the 24 h period you shall find the skin.
If the half-sphere rotating around a vertical axis at a speed radians / sec Object A contact with the surface of the tank and is at rest relative to the barrel. What if the skin surface, effortlessly every time h.