For an automobile with wheel base 2.5m, the centre of gravity lies 0.6 m above the ground and 1.15 m in front of the rear axle. The automobile is moving on level ground with a speed of 45 km/hr. Find the minimum stopping distance when

(a) Only rear wheels are braked
(b) Only front wheels are braked
(c) Brakes are applied to all the wheels
Take the value of coefficient of friction equal to 0.5.