"The lower part of a 2.0 meters high road sign is at a distance of 4.0 meters from the car drivers eyes. It's difficult to read the sign at such a distance, aswell as when the distance is too short. Investigate how the angle varies when the car is approaching on a straight road. At what distance is the angle as big as possible? The sign is readable if the angle is greater than 1. Investigate for how long time the sign will be readable" Thats the problem to solve. Of course the time depends on how fast one is driving. I haven't gotten anywhere with this problem. Please help me!