4 A ball \(B\) is projected from a point \(O\) on horizontal ground at an angle of \(40 ^ { \circ }\) above the horizontal. \(B\) hits the ground 1.8 s after the instant of projection. Calculate
- the speed of projection of \(B\),
- the greatest height of \(B\),
- the distance from \(O\) of the point at which \(B\) hits the ground.