A flat race track consists of two straight section AC and DB each of length 180 m and one semi circular section DC of radius R = 150 m. A car starting from rest at A has to reach B in least possible time (the car may cross through point B and need not stop there). The coefficient of friction between the tyres and the road is `mu = 0.6` and the top speed that the car can acquire is 180 kph. Find the minimum time needed to move from A to B under ideal conditions. Braking is not allowed in the entire journey [`g = 10 m//s^(2)`]