A vertical wind screen of a car is made up of two parts, as shown in figure, where the upper one A is 25cm vertically long and covers the 5cm of the lower piece B.The upper one is hinged at the top so that it can be opened outward, inclining to the vertical. The car is running on the horizontal road at 60km/hr in the rain which is falling vertically at 20km/hr. Find the maximum angle, through which the upper part A can be opened outward, such that the rain drops do not enter the car.

Answer

`[59^(@)]`