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.
Extracted text: 3. A closed cylindrical tank, 6 feet in diameter and 12 feet high contains water to a depth of 10 feet. It is rotated about its own vertical axis with a constant angular speed, w, which is equal to 210 revolutions per minute. How much area at the bottom is not covered by the liquid? A. 3.948 sq. ft. B. 2.202 sq. ft. C. 5.264 sq. ft D. 0.701 sq. ft.