4 A small ball \(B\) is projected from a point \(O\) with speed \(14 \mathrm {~m} \mathrm {~s} ^ { - 1 }\) at an angle of \(60 ^ { \circ }\) above the horizontal.
- Calculate the speed and direction of motion of \(B\) for the instant 1.8 s after projection.
The point \(O\) is 2 m above a horizontal plane.
- Calculate the time after projection when \(B\) reaches the plane.