20 A R [3] A closed cylindrical barrel of radius R and length L, is half full with oil of weight density w and lies on the ground on the edge AB as shown in Fig. 3. The force F exerted by the oil on the circular side is given by R F=2wxRxdx. Use the trapezoid rule with five 0 intervals and the term R2.2) of the Romberg algorithm to calculate the force F for R= 2 ft and w= 90 lb/ft. dx -6'- BI VR2 x2 Fig. 3. Fluid barrel x