Particle A of mass m
1
moving with velocity $\left( {\sqrt3\widehat i + \widehat j} \right)m{s^{ - 1}} collides with another particle B of mass m
2
which is at rest initially. Let \overrightarrow {{V_1}}
and \overrightarrow {{V_2}}
be the velocities of particles A and B after collision
respectively. If m
1
= 2m
2
and after
collision \overrightarrow {{V_1}} = \left( {\widehat i + \sqrt 3 \widehat j} \right)
, the angle between \overrightarrow {{V_1}}
and \overrightarrow {{V_2}} $
is :