An open circular cylinder full of water rotates on its vertical axis. It has a diameter of 20 cm and 30 cm long. Calculate the speed at which it should rotate to leave half of the bottom exposed.

An open cylindrical vessel, having its axis vertical, is 100 mm diameter and 150 mm deep and is exactly two-thirds full of water. If the vessel is rotated about its axis, determine at what steady angular velocity the water would just reach the rim of the vessel.

It is estimated that 91 percent of an iceberg's volume is below the surface, while only 9 percent is visible above the surface. For seawater with a density of 1025 kg/m³, estimate the density of the iceberg. The density of the iceberg is kg/m³