joints. In Figure 1, three men demonstrate the cantilever principle used in the Forth Bridge design. One man is suspended on a platform in the center. The platform is held aloft by the strength of two men, one on each side. These two men sit in chairs and each hold two broomsticks whose ends are wedged between their legs and chairs. Short ropes connect the center platform with the ends of the inner broomsticks. The outer broomsticks are attached to piles of bricks that serve as counterweights. Figure 1: (Top) Three men illustrate the cantilever principle of the Forth Bridge. (Bottom) The bridge spans a waterway in Scotland.Now, we will model the man on the left as a truss. To be sure the trusses are statically determinate, we treat the counterweights (the bricks and attached ropes) as external forces that are not part of the truss. Model A Model B FL Figure 4: The center and right images show two truss designs that might be used to model the man's torso, his arms, and the broomsticks. The supports (pinned and/or rolling) are not shown in the models. Assume the white and black arrow forces point straight down. 2. According to the method of joints, how many equations do you have for... a. [2 pts] the Model A truss (center image in Figure 4)? Explain. b. [2 pts] the Model B truss (right image in Figure 4)? Explain. 3. To balance the number of equations and number of unknowns, how many supports would you need for each truss? Recall that pinned supports have two unknowns and rolling supports have only one unknown. a. [2 pts] for the Model A truss b. [2 pts] for the Model B truss 4. Would you be able to use the Method of Joints to solve for forces in... a. [4 pts] the Model A truss? Explain. b. [4 pts] the Model B truss? Explain. 5. [4 pts] Choose the better model and update the truss sketch to include supports (be sure to indicate the type of support) and all external forces. This includes Fr, the force from the counterweight, and reaction forces at the support(s). 6. [6 pts] Assume the truss model is symmetric and that the man on the center platform weighs 700 N (so F1 is 350 N). How are the forces from the center platform and the pile of bricks related? Justify your answer. Note that a chair will push someone up but not suck them down