1. [Maximum mark: I 1] Two cars, A and B, are traveling at 60 km/h and 70 km/h respectively, on straight roads, as shown in the diagram below. The two roads intersect at the point 0 and the angle between the roads is 60\" At a given instant both cars are 5 km away from 0. Find (a) The rate of change of the distance between the cars, at that instant. [6 marks] (b) The rate of change of the angle 6 = ORB at that instant. [5 marks]