1. The problem statement, all variables and given/known data The leaning Tower of Pisa (Fig. 9-47) is 55 m high and 7.0 m in diameter. The top of the tower is displaced 4.5 m from the vertical. Treat the tower as a uniform, circular cylinder. (a) What additional displacement, measured at the top, will bring the tower to the verge of toppling? (b) What angle with the vertical will the tower make at that moment? 2. Relevant equations Net force in x-direction = 0 Net force in y-direction = 0 Net torque = 0 3. The attempt at a solution So this problem is confusing me a little. I'm a little confused as to what forces are being applied to this tower and where are the forces being applied. I know that there is a normal force, perpendicular to the ground from the base of the structure, there if a friction force in the x direction to the base of the structure, and there is gravity, which is being applied the the tower itself. However, where is gravity applying the object? At its center of mass or at the top of the tower?