23. The leaning Tower of Pisa (see 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. Treating 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? (The current rate of movement of the top is 1 mmlyear.)