A small mirror is attached to a vertical wall, and it hangs adistance of 1.59 m above the floor. The mirror is facing dueeast, and a ray of sunlight strikes the mirror early in the morningand then again later in the morning. The incident andreflected rays lie in a plane that is perpendicular to both thewall and the floor. Early in the morning, the refleted raystrikes the floor at a distance of 3.95 m from the base of thewall. Later on in the morning the ray is observed to strike the floor at a distance of 1.39 m from the wall. The earth rotates at a rate of 15.0o per hour. How much time(in hours) has elapsed between the two observations?