Two seconds after projection a projectile is travelling in a direction inclined at 30o to the horizontal after one more second, it is travelling horizontally, the magnitude and direction of its velocity are

Let in 2 seconds, the body reaches up to point A and after one more second up to point B.Total time of ascent for a body is given 3sec,  i.e., t=usin⁡θg=3∴usin⁡θ=10×3=30    .......(i)Horizontal component of velocity remains always constantucos⁡θ=vcos⁡30∘  .........(ii)For vertical upward motion between point O and A,vsin⁡30∘=usin⁡θ−g×2                [Using v=u−gt]vsin⁡30∘=30−20                              [ As usin⁡θ=30]∴v=20m/sSubstituting this value in equation (ii),ucos⁡θ=20cos⁡30∘=103   ..........(iii) From equations (i) and (iii), u=203 and θ=60∘