You are on a train that is traveling at 3.0 m/s along a level
straight track. Very near and parallel to the track is a wall
that slopes upward at a 12° angle with the horizontal. As you
face the window (0.923 m high, 1.92 m wide) in your compartment,
the train is moving to the left, as the drawing indicates. The
top edge of the wall first appears at window corner A and
eventually disappears at window corner B. How much time passes
between appearance and disappearance of the upper edge of the
wall?