試題詳解

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.