Airplanes A and B are flying with constant velocity in the same vertical plane at angles 30 and 60 with respect to the horizontal respectively as shown in the figure. The speed of A is 1003 ms . At time t = 0 s, an observer in A finds B at a distance of 500 m. This observer sees B moving with a constant velocity perpendicular to the line of motion of A. If at t= to, A just escapes being hit by B, to in seconds is A B 30 60