2. On a distant planet where the gravitational constant g = 6.0 m/s2, Sherlock Holmes dropped his pipe from the roof of a building. Dr. Watson, in a room below, noticed the pipe flash past a window, taking0.30 seconds to cover the 1.5 m vertical dimension of the window. Exactly 1.4 seconds after passing the bottom of the window on the way down, it passed it again on the way up, having made a perfectly elastic collision with the level ground below. Calculate the height of the building. (A) 7.1 m (B) 11.6 m (C) 9.4 m (D) 4.8 m (E) 8.5 m.