posted by A on .
A steel ball is dropped from rest from the roof of a building. An observer standing behind a window that is part way down the building 120 cm high notes the ball takes 0.125 s to fall from the top to the bottom of the window. The ball continues to fall, makes an elastic collision with the sidewalk and rebounds appearing at the bottom of the window 2.0 s after passing it on the way down. How tall is the building?