A body of mass m
1
moving with an unknown
velocity of ${v_1}\mathop i\limits^ \wedge , undergoes a collinear collision
with a body of mass m
2
moving with a velocity
{v_2}\mathop i\limits^ \wedge . After collision, m
1
and m
2
move with
velocities of {v_3}\mathop i\limits^ \wedge and {v_4}\mathop i\limits^ \wedge $ , respectively.
If m
2
= 0.5 m
1
and v
3
= 0.5 v
1
, then v
1
is :-