A closed cylindrical vessel of diameter 15 cm and length 100 cm contains water up to a height of 80 cm. The vessel is rotated at speed of 950 rpm about its vertical axis. Find the area in cm^2...

A closed cylindrical vessel of diameter 15 cm and length 100 cm contains water up to a height of 80 cm. The vessel is rotated at speed of 950 rpm about its vertical axis. Find the area in cm^2 uncovered at the base of the tank.