Problem 5: Method of Sections d Inputs: d = 4 m A B D E F D M H 1 J K L a a 3 m (all horizontal members are this length) P = 45 kN P There is a pin at A and a roller at G. Using the method of sections, determine the force in member CJ of the truss shown. State whether it is in tension or compression. Comments: As always, I'm just trying to get you to realize that something which looks complicated, actually isn't. Take a vertical section cut through your unknown member and keep the right side. That way we don't have to worry about reactions. Look at your FBD. One equation gets your value. Done. Easy right? Now consider this, would the FBD look any different if you were asked about DK instead? What could you say about all the diagonals in this truss? You can use this skill to rapidly assess tension vs. compression in the trusses around you. I will apologize in advance, but you will never look at trusses the same. You will always (1) see triangles, (2) think about T vs. C, and (3) wonder which members aren't carrying any load at a given time. Danger.... you're becoming an engineer!