A rectangular box L= 6 ft, W = 4 ft, and H = 5 ft is filled with water (pg = 62.5 lbs/ft3). a.) If the origin of the coordinates (x, y, z) = (0, 0, 0) is at the front, bottom corner of the above figure, what are the coordinates of the centroid? b.) How much work is done pumping the water to a point 3 feet higher than the top of the box? Use the method of centroids.