Two particles are moving in different circles in same plane with different angular velocities as shown in figure. At t=0, initial positions of particles A and B are shown by dots on the respective circles. Initial distance between particles is 1 m. Particle A move anticlockwise in the first circle whereas B moves clockwise in the second circle. Angle described (rotated) by A and B in time ′t′ are θA=(π2t) and θB=(πt) respectively. Here θ is in radian and t is in second. Radius of each circle is shown in diagram. At time t=2 s, the angular velocity of the particle A with respect to the particle B is