3. A 3-ft-long gate of uniform density is closed at 45 with respect to the interface between water and oil. Th width of the gate (into the paper) is 5 ft. The specific gravity of oil is 0.8, where specific gravity is define by the ratio of density with respect to the density of water at the same temperature. The gravitation acceleration is 32.2 ft/s2. Note that Patm 2116 lb/ft and = PHO 1.94 slug/ft. Ignore friction at the hing = (a) Using the manometer reading, estimate the absolute pressure at the top of the tank (inside). (b) Evaluate the locations of centroid and center of pressure for the gate. (c) Calculate the minimum weight of the gate so that it is kept closed. 3 ft hinge 45 oil 2 ft. water 3 ft