A body has an initial velocity of 3 m/s and has an acceleration of 1 m/s2 normal to the direction of thi initial velocity. Then its velocity 4 seconds after the start is :- 7 m/s along the direction of initial velocity 7 m/s along the normal to the direction of initial velocity 3 7 m/s mid-way between the two directions 5 m/s at an angle off tan-' (4/3) with the direction of initial velocity