3. Using Method of sections a. determine the reaction forces at A and B (5 points) b. determine the forces in members DF, EF and EI of the frame for the loading given below. P1, P2 and P 3 are acting vertically downward. State if the members are in tension or compression. (15 points) First draw the free body diagram (FBD) by clearly indicating all external forces . Without a FBD your solution will not be graded P1 75 kN P1 P2 P3 P2 20 kN P3 50 kN 7 D a m H b m -a -a --a -a